JP2012157151A - Power supply unit and electronic apparatus using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply unit capable of suppressing the load of a system and to provide an electronic apparatus using the same.SOLUTION: The present invention includes: a plurality of power supply sections A-G that each generate output voltages V1-V7 of different systems and a sequence control section X that receives an input of an enable signal EN1 and on-off controls the plurality of power supply sections A-G in a predetermined order.

Description

  The present invention relates to a multi-output type power supply device that generates a plurality of output voltages, and an electronic apparatus using the same.

  FIG. 5 is a diagram illustrating a conventional example of a power supply device. The power supply device 100 of the conventional example includes a first power supply unit 101 that generates an output voltage V1, a second power supply unit 102 that generates an output voltage V2, a third power supply unit 103 that generates an output voltage V3, and an output voltage. And a fourth power supply unit 104 that generates V4.

  Enable signals EN1 to EN4 are input in parallel from the main controller 200 to the power supply device 100 of this conventional example, and the power supply units 101 to 104 are on / off controlled according to the enable signals EN1 to EN4, respectively. .

  As an example of the related art related to the above, Patent Document 1 can be cited.

JP 2007-259634 A

  By the way, in the multi-output type power supply device 100, in consideration of the safety of the system, the power supply device 100 is turned on in order from the power supply unit with the lower output voltage target value when the power supply device 100 is started. Sometimes, it is required to turn off the power supply unit in order from a higher output voltage target value. In such a case, the main controller 200 must control the generation timing of the enable signals EN1 to EN4 in order to realize a desired on / off sequence (on / off order of the power supply units 101 to 104). The load on the main controller 200 (the load on the system side on which the power supply apparatus 100 is mounted) has increased.

  In view of the above-described problems found by the inventors of the present application, an object of the present invention is to provide a power supply device capable of reducing the load on the system and an electronic apparatus using the same.

  In order to achieve the above object, a power supply device according to the present invention includes a plurality of power supply units each generating an output voltage of a different system, and an ON / OFF of the plurality of power supply units in a predetermined order upon receiving an enable signal. And a sequence control unit that performs off control (first configuration).

  In the power supply device having the first configuration described above, the sequence control unit may be configured to turn on sequentially from a power supply unit having a lower output voltage target value when the power supply device is started up (second configuration). Good.

  Further, in the power supply device having the second configuration, when the power supply device is stopped, the sequence control unit is configured to be sequentially turned off from a power supply unit having a higher output voltage target value (third configuration). Good.

  Further, in the power supply device having the third configuration, the sequence control unit detects that the output voltage of the power supply unit that has been turned on first rises when the power supply device is started up, and is to be turned on next time. When the power supply apparatus is stopped, it is preferable to detect that the output voltage of the power supply section that was turned off first falls and to turn off the power supply section that should be turned off next (fourth structure).

  Further, in the power supply device having the fourth configuration, the sequence control unit compares the plurality of output voltages with a threshold voltage set for each to generate a plurality of output detection signals. And an on / off control signal generation unit that generates a plurality of on / off control signals from the enable signal and the plurality of output detection signals and supplies the plurality of on / off control signals to the plurality of power supply units, Configuration).

  In the power supply device having the fifth configuration, the threshold voltage may be configured to have a hysteresis (sixth configuration).

  The power supply device having the sixth configuration may have a configuration (seventh configuration) having an external terminal for outputting the plurality of output detection signals to the outside of the power supply device.

  According to another aspect of the present invention, there is provided an electronic apparatus including a power supply device having any one of the first to seventh configurations, a main controller that supplies the enable signal to the power supply device, and a plurality of output voltages to which the plurality of output voltages are supplied. It is set as the structure (8th structure) which has this load.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the power supply device which can reduce the load by the side of a system, and an electronic device using the same.

The figure which shows one Embodiment of the power supply device which concerns on this invention The figure which shows the example of 1 structure of the sequence control part X Time chart showing an operation example of the sequence control unit X The figure which shows the modification of the power supply device which concerns on this invention Figure showing a conventional example of a power supply

<Overall configuration>
FIG. 1 is a diagram showing an embodiment of a power supply device according to the present invention. In terms of circuit blocks, the power supply device 1 of the present embodiment includes a first step-down DC / DC converter A, a second step-down DC / DC converter B, a step-up DC / DC converter C, a positive charge pump D, And a sequence control unit X.

  In this specification, the first step-down DC / DC converter A, the second step-down DC / DC converter B, the step-up DC / DC converter C, and the positive charge pump D are referred to as power supply units A to D as appropriate. Sometimes abbreviated.

  The first step-down DC / DC converter A is a step-down switching regulator that steps down the power supply voltage VCC and generates an output voltage V1. The first step-down DC / DC converter A includes a P-channel MOS [Metal Oxide Semiconductor] field effect transistor A1, an N-channel MOS field effect transistor A2, an inductor A3, resistors A4 to A8, and capacitors A9 to A11. , Switch control unit A12.

  The source and back gate of the transistor A1 are both connected to the application terminal of the power supply voltage VCC. The drain of the transistor A1 is connected to the first end of the inductor A3. The gate of the transistor A1 is connected to the switch control unit A12. The source and back gate of the transistor A2 are both connected to the ground terminal. The drain of the transistor A2 is connected to the first end of the inductor A3. The gate of the transistor A2 is connected to the switch control unit A12. The second end of the inductor A3 is connected to the application end of the output voltage V1. The resistor A4 is connected between the gate of the transistor A1 and the application end of the power supply voltage VCC. The resistor A5 is connected between the gate of the transistor A2 and the ground terminal. A series circuit including the resistors A6 and A7 is connected between the application terminal of the output voltage V1 and the ground terminal. A connection node between the resistor A6 and the resistor A7 is connected to the switch control unit A12 and the sequence control unit X as an application end of the feedback voltage FB1. A series circuit including a resistor A8 and a capacitor A9 is connected between both ends of the resistor A6. The capacitor A10 is connected between the application terminal of the power supply voltage VCC and the ground terminal. The capacitor A11 is connected between the application terminal of the output voltage V1 and the ground terminal.

  The switch control unit A12 operates in response to the input of the power supply voltage VCC, and performs switching control of the transistors A1 and A2 so that the feedback voltage FB1 matches the target value. The switch control unit A12 is on / off controlled according to the on / off control signal S1 input from the sequence control unit X.

  Of the above-described components, the switch control unit A12 is integrated in the semiconductor device Y, and the other circuit elements A1 to A11 are all externally attached to the semiconductor device Y.

  The second step-down DC / DC converter B is a step-down switching regulator that steps down the power supply voltage VCC to generate the output voltage V2. The second step-down DC / DC converter B includes a P-channel MOS field effect transistor B1, an N-channel MOS field effect transistor B2, an inductor B3, resistors B4 to B6, capacitors B7 to B9, and a switch control unit B10. And including.

  The source and back gate of the transistor B1 are both connected to the application terminal of the power supply voltage VCC. The drain of the transistor B1 is connected to the first end of the inductor B3. The gate of the transistor B1 is connected to the switch control unit B10. The source and back gate of the transistor B2 are both connected to the ground terminal. The drain of the transistor B2 is connected to the first end of the inductor B3. The gate of the transistor B2 is connected to the switch control unit B10. The second end of the inductor B3 is connected to the application end of the output voltage V2. The series circuit including the resistors B4 and B5 is connected between the application terminal of the output voltage V2 and the ground terminal. A connection node between the resistor B4 and the resistor B5 is connected to the switch control unit B10 and the sequence control unit X as an application terminal of the feedback voltage FB2. A series circuit including a resistor B6 and a capacitor B7 is connected between both ends of the resistor B4. The capacitor B8 is connected between the application terminal of the power supply voltage VCC and the ground terminal. The capacitor B9 is connected between the application terminal of the output voltage V2 and the ground terminal.

  The switch control unit B10 performs switching control of the transistors B1 and B2 so that the feedback voltage FB2 matches the target value. The switch control unit B10 is on / off controlled in accordance with the on / off control signal S2 input from the sequence control unit X.

  Of the above-described components, the transistor B1, the transistor B2, and the switch control unit B10 are all integrated in the semiconductor device Y, and the other circuit elements B3 to B9 are all externally attached to the semiconductor device Y. Has been.

  The step-up DC / DC converter C is a step-up type switching regulator that steps up the power supply voltage VCC and generates an output voltage V3. The step-up DC / DC converter C includes P-channel MOS field effect transistors C0 and C1, an N-channel MOS field effect transistor C2, an inductor C3, resistors C4 to C8, capacitors C9 to C12, and a switch control unit C13. And including.

  The source and back gate of the transistor C0 are both connected to the application terminal of the power supply voltage VCC via the resistor C7, and are also connected to the switch control unit C13. The drain of the transistor C0 is connected to the first end of the inductor C3. The gate of the transistor C0 is connected to the switch control unit C13. The source and back gate of the transistor C1 are both connected to the application terminal for the output voltage V3. The drain of the transistor C1 is connected to the second end of the inductor C3. The gate of the transistor C1 is connected to the switch control unit C13. The source and back gate of the transistor C2 are both connected to the ground terminal. The drain of the transistor C2 is connected to the second end of the inductor C3. The gate of the transistor C2 is connected to the switch control unit C13. A series circuit composed of the resistor C4 and the resistor C5 is connected between the application terminal of the output voltage V3 and the ground terminal. A connection node between the resistor C4 and the resistor C5 is connected to the switch control unit C13 and the sequence control unit X as an application end of the feedback voltage FB3. A series circuit including a resistor C6 and a capacitor C11 is connected between both ends of the resistor C4. The capacitor C9 is connected between the application terminal of the power supply voltage VCC and the ground terminal. The capacitor C10 is connected between the application terminal of the output voltage V3 and the ground terminal. A series circuit including a resistor C8 and a capacitor C12 is connected to the switch control unit C13 as a phase compensation circuit.

  The switch control unit C13 performs switching control of the transistors C1 and C2 so that the feedback voltage FB3 matches the target value. The switch control unit C13 is on / off controlled according to the on / off control signal S3 input from the sequence control unit X. In addition, the switch control unit C13 has a function of performing switching control of external transistors in place of switching control of the transistors C1 and C2 in accordance with an operation mode selection signal SEL input externally (in parentheses in the figure). See attached part). The switch control unit C13 also has a function of turning off the transistor C0 and shutting down the boosting operation when the inductor current becomes excessive.

  Of the above-described components, the transistor C1, the transistor C2, and the switch control unit C13 are all integrated in the semiconductor device Y, and the other circuit elements C3 to C12 are all externally attached to the semiconductor device Y. Has been.

  The positive charge pump D is a positive boost type charge pump that boosts the power supply voltage VCC to generate an output voltage V4 by combining a capacitor and a switch. The positive charge pump D includes P-channel MOS field effect transistors D1 and D2, N-channel MOS field effect transistors D3, diodes (switches) D4 to D7, resistors D8 and D9, capacitors D10 to D14, and switches And a control unit D15.

  The source and back gate of the transistor D1 are both connected to the application terminal for the output voltage V3. The drain of the transistor D1 is connected to the anode of the diode D4. The gate of the transistor D1 is connected to the switch control unit D15. The source and back gate of the transistor D2 are both connected to the anode of the diode D4. The drains of the transistors D2 and D3 are both connected to the first ends of the capacitors D11 and D12. The gates of the transistors D2 and D3 are both connected to the switch control unit D15. The source and back gate of the transistor D3 are both connected to the ground terminal. Both the cathode of the diode D4 and the anode of the diode D5 are connected to the second end of the capacitor D11. Both the cathode of the diode D5 and the anode of the diode D6 are connected to the first terminal of the capacitor D13. A second terminal of the capacitor D13 is connected to the ground terminal. Both the cathode of the diode D6 and the anode of the diode D7 are connected to the second end of the capacitor D12. The cathode of the diode D7 is connected to the application terminal for the output voltage V4. The series circuit composed of the resistor D8 and the resistor D9 is connected between the application terminal of the output voltage V4 and the ground terminal. A connection node between the resistor D8 and the resistor D9 is connected to the switch control unit D15 and the sequence control unit X as an application end of the feedback voltage FB4. The capacitor D10 is connected between the application terminal of the output voltage V3 and the ground terminal. The capacitor D14 is connected between the application terminal of the output voltage V4 and the ground terminal.

  The switch control unit D15 operates in response to the input of the output voltage V3, and performs switching control of the transistors D1 to D3 so that the feedback voltage FB4 matches the target value. The switch control unit D15 is on / off controlled in accordance with the on / off control signal S4 input from the sequence control unit X.

  Of the above-described components, the transistors D1 to D3 and the switch control unit D15 are all integrated in the semiconductor device Y, and the other circuit elements D4 to D14 are all externally attached to the semiconductor device Y. ing.

  The sequence control unit X is integrated in the semiconductor device Y and receives the enable signal E1 from a main controller (not shown) provided outside the power supply device 1 to turn on / off control signals S1 to S4 described above. And on / off control of the power supply units A to D is performed in a predetermined order.

  Specifically, the sequence control unit X generates the on / off control signals S1 to S4 so that the power supply device 1 is turned on in order from the power supply unit having the lower target value of the output voltage when the power supply device 1 is started. When the power supply device 1 is stopped, the on / off control signals S <b> 1 to S <b> 4 are generated so that the power supply unit having the higher output voltage target value is turned off in order. That is, when V1 (target value) <V2 (target value) <V3 (target value) <V4 (target value), the sequence control unit X, when starting up the power supply device 1, is the first step-down DC / DC converter A. On / off control signals S1 to S4 are generated so that the second step-down DC / DC converter B, the step-up DC / DC converter C, and the positive charge pump D are turned on in this order. On / off control signals S1 to S4 are generated so that the positive charge pump D, the step-up DC / DC converter C, the second step-down DC / DC converter B, and the first step-down DC / DC converter A are turned off in this order.

  Further, the sequence control unit X generates output detection signals PG1 to PG4 by comparing the output voltages V1 to V4 with the threshold voltages set for each, and outputs the output detection signals PG1 to PG4 to the outside of the power supply device 1 via the external terminals. . The signal lines to which the output detection signals PG1 to PG4 are transmitted are pulled up to the application terminal of the constant voltage REG via external resistors R1 to R4, respectively. The output detection signals PG1 to PG4 are used when it is confirmed that the rising / falling of the output voltages V1 to V4 has been correctly completed outside the power supply device 1. On the other hand, the above-described output detection signals PG1 to PG4 / Off control signals S1 to S4 are also used when generating.

  In FIG. 1, the configuration in which the output detection signals PG1 to PG3 output to the outside of the semiconductor device Y are re-input into the semiconductor device Y as enable signals EN2 to EN4 is depicted. The present invention is not limited to this, and the configuration may be such that the output detection signals PG1 to PG3 are read as enable signals EN2 to EN4 inside the sequence control unit X. When the latter configuration is adopted, the external terminals for inputting the enable signals EN2 to EN4 are not necessary, and the size of the semiconductor device Y can be reduced. In any case, only one system of the enable signal EN1 needs to be supplied from the outside of the power supply device 1 (main controller).

<Sequence control unit>
FIG. 2 is a diagram illustrating a configuration example of the sequence control unit X. The sequence control unit X of this configuration example includes an output detection signal generation unit X10 and an on / off control signal generation unit X20.

  The output detection signal generation unit X10 is a circuit block that generates the output detection signals PG1 to PG4 by comparing the feedback voltages FB1 to FB4 (divided voltages of the output voltages V1 to V4) with the threshold voltages set for each. Yes, including 4 Schmitt triggers X11-X14. A predetermined hysteresis is given to each threshold voltage of the Schmitt triggers X11 to X14. By adopting such a configuration, it is possible to increase resistance to noise.

  The on / off control signal generator X20 is a circuit block that generates the on / off control signals S1 to S4 from the enable signal EN1 and the output detection signals PG1 to PG4. including. The OR gate X21 performs an OR operation between the enable signal EN1 and the output detection signal PG2 (= enable signal EN3). The output signal of the OR gate X21 is output as the on / off control signal S1. The OR gate X22 performs an OR operation between the enable signal EN1 and the output detection signal PG3 (= enable signal EN4). The OR gate X23 performs an OR operation between the enable signal EN1 and the output detection signal PG4. The AND gate X24 performs an AND operation between the enable signal EN1 and the output detection signal PG3 (= enable signal EN4). The output signal of the AND gate X24 is output as an on / off control signal S4. The AND gate X25 performs an AND operation between the output signal of the OR gate X22 and the output detection signal PG1 (= enable signal EN2). The output signal of the AND gate X25 is output as the on / off control signal S2. The AND gate X26 performs an AND operation between the output signal of the OR gate X23 and the output detection signal PG2 (= enable signal EN3). The output signal of the AND gate X26 is output as an on / off control signal S3.

<Time chart>
FIG. 3 is a time chart showing an operation example of the sequence control unit X. From the top, the enable signal EN1, the on / off control signal S1, the output voltage V1, the output detection signal PG1 (= enable signal EN2), and on / Off control signal S2, output voltage V2, output detection signal PG2 (= enable signal EN3), on / off control signal S3, output voltage V3, output detection signal PG3 (= enable signal EN4), on / off control signal S4, The output voltage V4 and the output detection signal PG4 are depicted.

  When the enable signal EN1 is raised from the low level to the high level at time t1, the on / off control signal S1 is raised from the low level to the high level. As a result, the first step-down DC / DC converter A is activated and the output voltage V1 starts to rise.

  At time t2, when the output voltage V1 exceeds a predetermined threshold voltage and the output detection signal PG1 is raised from the low level to the high level, the on / off control signal S2 is raised from the low level to the high level. As a result, the second step-down DC / DC converter B is activated and the output voltage V2 starts to rise.

  At time t3, when the output voltage V2 exceeds a predetermined threshold voltage and the output detection signal PG2 is raised from the low level to the high level, the on / off control signal S3 is raised from the low level to the high level. As a result, the step-up DC / DC converter C is activated and the output voltage V3 starts to rise.

  At time t4, when the output voltage V3 exceeds a predetermined threshold voltage and the output detection signal PG3 is raised from the low level to the high level, the on / off control signal S4 is raised from the low level to the high level. As a result, the positive charge pump D is activated and the output voltage V4 starts to rise.

  At time t5, the output voltage V4 exceeds a predetermined threshold voltage, and the output detection signal PG4 is raised from the low level to the high level. At this point, the activation of the power supply units A to D is completed.

  When the enable signal EN1 falls from the high level to the low level at time t6, the on / off control signal S4 falls from the high level to the low level. As a result, the positive charge pump D is stopped and the output voltage V4 starts to decrease.

  At time t7, when the output voltage V4 falls below a predetermined threshold voltage and the output detection signal PG4 falls from the high level to the low level, the on / off control signal S3 falls from the high level to the low level. As a result, the step-up DC / DC converter C is stopped and the output voltage V3 starts to decrease.

  At time t8, when the output voltage V3 falls below a predetermined threshold voltage and the output detection signal PG3 falls from the high level to the low level, the on / off control signal S2 falls from the high level to the low level. As a result, the second step-down DC / DC converter B is stopped and the output voltage V2 starts to decrease.

  At time t9, when the output voltage V2 falls below a predetermined threshold voltage and the output detection signal PG2 falls from the high level to the low level, the on / off control signal S1 falls from the high level to the low level. As a result, the first step-down DC / DC converter A is stopped and the output voltage V1 starts to decrease.

  At time t10, the output voltage V1 falls below a predetermined threshold voltage, and the output detection signal PG1 falls from the high level to the low level. At this point, the power supply units A to D are all stopped.

  As described above, the sequence control unit X generates the on / off control signals S1 to S4 so that the power supply device 1 is turned on in order from the power supply unit having the lower target value of the output voltage when the power supply device 1 is started. When the power supply device 1 is stopped, the on / off control signals S1 to S4 are generated so that the power supply unit having the higher output voltage target value is turned off in order. With such a configuration, it is possible to improve the safety of the system.

  Further, when looking at the entire system in which the power supply device 1 is mounted, it is necessary to supply one system enable signal from the outside (main controller) of the power supply device 1 in order to realize the on / off sequence described above. Only EN1. Accordingly, it is possible to contribute to reducing the load on the main controller and saving the system space.

  Further, the sequence control unit X detects that the output voltage of the power supply unit that was turned on first rises when the power supply device 1 is started up, turns on the power supply unit that should be turned on next, and first stops when the power supply device 1 is stopped. It is configured to detect that the output voltage of the turned off power supply unit has fallen and turn off the power supply unit to be turned off next. With such a configuration, it is possible to improve the certainty of the on / off sequence.

<Other variations>
In the embodiment described above, the configuration in which the present invention is applied to a power supply device including a 4-channel power supply unit has been described as an example. However, the number of output channels is not limited to the above embodiment. In addition, the present invention can be widely applied to all multi-output power supply devices that generate a plurality of output voltages.

  For example, in FIG. 4, seven-channel power supply units A to G (first step-down DC / DC converter A, second step-down DC / DC converter B, and the like) that supply output voltages V1 to V7 of different systems to loads 3a to 3g, respectively. Power supply device 1 (system power supply for a liquid crystal panel) including a step-up DC / DC converter C, a positive charge pump D, a negative charge pump E, a common voltage generation unit F, and a high voltage LDO [Low Drop-Out] regulator G) IC) is depicted. In such a multi-channel power supply device 1, if a sequence control unit X that receives only the enable signal EN 1 from the main controller 2 and performs on / off control of the power supply units A to G in a predetermined order is provided, It is possible to greatly reduce the load on the controller 2 (the load on the system side on which the power supply device 1 is mounted).

  The configuration of the present invention can be variously modified within the scope of the present invention in addition to the above embodiment. That is, the above-described embodiment is an example in all respects and should not be considered as limiting, and the technical scope of the present invention is not the description of the above-described embodiment, but the claims. It should be understood that all modifications that come within the meaning and range of equivalents of the claims are included.

  For example, in the above embodiment, the case where the on / off timing is different for every power supply unit has been described as an example. However, the configuration of the present invention is not limited to this, and a plurality of power supply units Of these, there may be ones with the same on / off timing.

  In the above embodiment, the power supply device is turned on in order from the power supply unit with the lower target value of the output voltage when starting up, and the power supply unit is turned off in turn from the power supply unit with the higher target value of output voltage when the power supply device is stopped. The configuration has been described as an example, but the configuration of the present invention is not limited to this, and an on / off sequence other than the above may be used.

  The multi-output type power supply device according to the present invention can be used as, for example, a system power supply IC for a liquid crystal panel.

DESCRIPTION OF SYMBOLS 1 Power supply device 2 Main controller 3a-3g Load A 1st step-down DC / DC converter B 2nd step-down DC / DC converter C Step-up DC / DC converter D Positive charge pump E Negative charge pump F Common voltage generation part G High voltage LDO regulator X sequence controller X10 output detection signal generator X20 on / off control signal generator

Claims (8)

A plurality of power supply units each generating an output voltage of a separate system;
A sequence control unit that receives input of an enable signal and performs on / off control of the plurality of power supply units in a predetermined order;
A power supply device comprising:   2. The power supply device according to claim 1, wherein the sequence control unit is turned on in order from a power supply unit having a lower output voltage target value when the power supply device is activated.   The power supply device according to claim 2, wherein the sequence control unit is turned off in order from a power supply unit having a higher output voltage target value when the power supply device is stopped.   The sequence control unit detects that the output voltage of the power supply unit that was turned on first rises when the power supply device starts up, turns on the power supply unit that should be turned on next, and turns off first when the power supply device stops The power supply device according to claim 3, wherein the power supply unit to be turned off next is turned off by detecting that the output voltage of the power supply unit has fallen. The sequence controller is
An output detection signal generation unit that generates a plurality of output detection signals by comparing the plurality of output voltages with a threshold voltage set for each of the plurality of output voltages;
An on / off control signal generation unit that generates a plurality of on / off control signals from the enable signal and the plurality of output detection signals and supplies the plurality of on / off control signals to the plurality of power supply units;
The power supply device according to claim 4, comprising:   The power supply device according to claim 5, wherein hysteresis is given to the threshold voltage.   The power supply apparatus according to claim 6, further comprising an external terminal for outputting the plurality of output detection signals to the outside of the power supply apparatus. The power supply device according to any one of claims 1 to 7,
A main controller for supplying the enable signal to the power supply;
A plurality of loads to which the plurality of output voltages are supplied;
An electronic device comprising:

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