JPH02269497A - Power source system for motor - Google Patents

Abstract

PURPOSE:To improve pulse load characteristic and to reduce in size by generating a pulse current from a drive switch, instructing a pulse current necessary for the operation of a stepping motor to the switch by a drive controller, and stopping the motor by the output detector when the voltage is reduced. CONSTITUTION:A pulse current Iout is supplied to a stepping motor 30 by ON/OFF of a drive switch 20, and the output voltage Vout of a DC power source 10 is reduced. When the voltage Vout becomes a first threshold value voltage or less, a signal H/L becomes L, and drive impossibility is informed to a drive controller 40. The controller 40 keeps on turning OFF the switch 20 until the signal H/L becomes H. When the voltage Vout is recovered to reach a second threshold value voltage, the signal H/L becomes H, and the controller 40 again turns ON/OFF the switch 20.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a motor power supply system using a DC stabilized power supply, and particularly to improving the pulse load characteristics of the power supply.

<Prior Art> Motors used in printers, disk drives, etc. are supplied with pulsed current from a power source.

By the way, in the case of a motor that moves a mechanical part, current is consumed at a peak at the start of operation, etc., so the following measures are taken on the power supply side to supply this pulse current.

■ Ensure power supply capacity is sufficient to continuously supply pulsed peak current.

■ Insert a large capacitor at the output end.

<Problems to be Solved by the Invention> However, the first problem with the conventional method is as follows. In (2), a current capacity larger than necessary is provided, which increases the size of the power supply and the manufacturing cost. In the case of ■, the size does not increase in the case of ■, but the rush current when the power is turned on increases.

In addition, in such applications, the DC power supply has multiple outputs, and in addition to outputting pulse current for driving the motor, it also supplies power to the logic section. In this case, the logic output (+5V), which requires output voltage accuracy, is used as the main output.
Pulse current output is used as slave output. by the way,
Since the power consumption of logic circuits is decreasing, the minimum current value of the main output is decreasing. For this reason, the pulse current that is the slave output becomes too large compared to the main output, making it impossible to stably supply the pulse current.
I don't like the challenge.

The present invention solves the above-mentioned problems (1) and (3), and its first object is to provide a small-sized motor power supply system with good pulse load characteristics. In addition, by solving the second problem above,
A second object of the present invention is to provide a motor power supply system with good pulse load characteristics that can stably supply a slave output even when the main output is small.

Means for Solving the Problems> A first invention that achieves the first object includes a DC power supply, a drive switch that converts the current output from the DC power supply into a pulse current, and the drive switch. a stepping motor operated by a pulse current; a drive control circuit that turns this drive switch on and off; and a drive control circuit that monitors the output voltage of the DC power supply and controls the drive control circuit when the voltage drops below a first threshold voltage (Vth1). An operation inhibit signal is output to the circuit, and the second threshold voltage (V
The present invention is characterized by comprising an output detection circuit that outputs an inhibition release signal to the drive control circuit when the drive control circuit recovers to th2).

A second invention that achieves the second object is a DC power supply having a main output and a slave output, a drive switch that converts the current output from the slave output into a pulse current, and a pulse current of the drive switch. A stepping motor operated by electric current, a first control signal for turning on and off the drive switch, and a second control signal for indicating whether or not the first control signal is operating the drive switch. A drive control circuit that outputs a drive control circuit, and an active dummy circuit that is connected to the main output, is controlled by the second control signal, and consumes a current larger than the current that makes the pulse load supply on the main output side unstable. It is set up.

When the drive switch is in operation, the active dummy circuit is operated, and when the drive switch is in the stopped state, the active dummy circuit is stopped.

For Kusaku Each component of the first invention operates as follows.

The drive switch generates pulsed current from direct current,
Used to drive a stepping motor.

The drive control circuit instructs the drive switch about the pulse current necessary for the desired operation of the stepping motor. The output detection circuit monitors the voltage supplied to the drive switch of the DC power supply, and when the voltage drops excessively, it stops the operation of the stepping motor via the drive control circuit and waits for the voltage to recover. It is now working again.

Each component of the second invention operates as follows.

The drive control circuit outputs a second control signal indicating whether or not the drive switch is operated.

The active dummy circuit is turned on during slave operation to increase main output current consumption and stabilize the output, and turned off when slave is not operated to reduce main output loss.

<Example> The present invention will be explained below using the drawings.

FIG. 1 is a configuration block diagram showing an embodiment of the first invention. In FIG. 6, a DC power supply 10 is a multi-output switching regulator, which has a logic output as a main output and a pulse output as a slave output. have. The drive switch 20 turns on and off the slave output of the DC power supply 10 to generate a pulse train signal. The stepping motor 30 is operated by a pulse signal output from the drive switch 20, and is used, for example, to feed paper or move a carriage in a printer. The live control circuit 40 is a circuit that outputs a signal to control the on/off of the drive switch 20, and starts its operation in response to a drive command signal from the outside, and returns an end signal when the instructed operation is completed. The output detection circuit 50 is a circuit that monitors the pulse output voltage v111L of the DC power supply 10, and when it falls below a first threshold voltage (Vth1), outputs an operation inhibit signal to the drive control circuit, and outputs an operation inhibit signal to the drive control circuit. When it recovers to the threshold voltage (V (<V, h1)), it outputs an inhibition release signal to the drive control circuit h2.

Here, the operation inhibition signal corresponds to the OFF state of the control signal supplied by the output detection circuit 50 to the drive control circuit 40, and the inhibition release signal corresponds to the H state. In addition, the first threshold voltage (
For example, Vthl) may be the lower limit voltage for stable operation of a load (for example, a printer), and the second threshold voltage (Vthz) may be the voltage at which the load can operate. The logic voltage is obtained from the main output of the DC power supply 10.

The operation of the device configured in this manner will be described next. Second
The figure is a waveform diagram explaining the operation of the device shown in FIG. Signal H/L
It is. A pulse current i out is supplied to the stepping motor 30 by turning the drive switch 20 on and off.
Accordingly, the output voltage vout of the DC power supply 10 decreases. When the output voltage Vfi becomes equal to or lower than the first threshold voltage (vlh1), the signal H/L becomes L and the drive control circuit 4
0 is not able to drive.

The drive control circuit 40 continues to turn off the drive switch 20 until the signal H/L becomes H. Output voltage V, Il
When l recovers and reaches the second threshold voltage (Vth2'), the signal H/L becomes H, and the drive control circuit 40 turns on and off the drive switch 20 again. Generates the instructed n pulses and ends the operation.

Next, the second invention will be explained. FIG. 3 is a mechanical block diagram explaining the second invention.

In FIG. 3, components having the same functions as those in FIG. A second control signal (1) 8 indicating whether or not the first control signal I is operating the drive switch 20 is output. The active dummy circuit 60 is connected to the main output of the DC power supply 10, and the amount of dummy current I2 is controlled by the second control signal I8.

FIG. 4 is an explanatory diagram of the dummy electrician 2, with the vertical axis representing the slave output voltage V and the horizontal axis representing the main output current I.

The shaded area is the unstable region where the slave output pulse current cannot be stably supplied. When the current consumption Ib of the logic circuit is small, it enters an unstable region and the slave output voltage 8 becomes unstable. Therefore, if the dummy current (2) is caused to flow and the consumption current Ia is increased, it enters a stable region and becomes a desirable state for the load that consumes the pulse current Is. That is, the following equation holds.

Ia=Ib+12 (+) The dummy current I2 is set to a value larger than the current required to break out of the unstable region from the current It consumed in the logic circuit. This value should be set so that the slave output voltage V is sufficiently high on the solid line in FIG.

FIG. 5 is a diagram showing the relationship between the pulse current I and the second control signal 8. The second control signal IN is an active dummy circuit driving pulse that includes a pulse train of pulse current . When a pulse train exists in pulse current I, dummy current I2 flows and current consumption increases to Ia, and when pulse current I does not include a pulse train, dummy current I2 does not flow and current consumption increases to Ib. This is reducing losses.

FIG. 6 is a comparative example with the second invention, which takes up the case where the active dummy circuit 60 is controlled by the DC power supply 10.
(F) is a pulse current, (G) is a dummy current, and (H) is a slave output voltage. Pulse current DC type H10
is detected and turns on the dummy current. Then, the power supply control system responds and the slave output voltage V rises. In this case, there is a delay in the response and the active dummy circuit has no effect during the first 1 to 2 pulses.In the circuit of FIG. 3, the drive control circuit 40 directly controls the active dummy circuit 60, so the response is delayed. There is no delay and the active dummy circuit functions from the beginning.

<Effects of the Invention> As explained above, according to the first invention, since the output detection circuit 50 confirms that the voltage of the DC power supply 10 is within the stable operation range of the load, the maximum voltage corresponding to the load is It has the advantage of being able to extract power from a DC power source and being compact. Furthermore, even if the capacity of the DC power source is increased, the drive control circuit 40 can be used as is, providing great versatility.

According to the second invention, since the active dummy circuit 60 is turned on only for a necessary period using the drive control circuit 40, there is no response delay, the pulse output is stable, and the active dummy circuit 60 is turned on only for a necessary period. Power consumption can be reduced and downsizing is possible.

[Brief explanation of drawings]

FIG. 1 is a configuration block diagram showing an embodiment of the first invention;
FIG. 2 is a waveform diagram explaining the operation of the device in FIG. 1, FIG. 3 is a configuration block diagram explaining the second invention, FIG. 4 is an explanatory diagram of the dummy current I2, and FIG. 5 is a pulse current I , and the second control signal IN, and FIG. 6 is a detailed explanatory diagram of the second invention.

Claims (2)

[Claims] (1) A DC power supply, a drive switch that converts the current output from the DC power supply into a pulse current, a stepping motor that operates with the pulse current of this drive switch, a drive control circuit that turns on and off this drive switch, and the above-mentioned. The output voltage of the DC power supply is monitored, and when it falls below a first threshold voltage (V_t_h_1), an operation inhibiting signal is output to the drive control circuit, and the voltage is recovered to a second threshold voltage (V_t_h_2). A power supply system for a motor, comprising: an output detection circuit that outputs an inhibition release signal to the drive control circuit. (2) A DC power supply that has a main output and a slave output, a drive switch that converts the current output from this slave output into a pulse current, a stepping motor that is operated by the pulse current of this drive switch, and a stepping motor that turns this drive switch on and off. a drive control circuit that outputs a first control signal that operates the drive switch; and a drive control circuit that outputs a second control signal that indicates whether or not the first control signal is operating the drive switch; , an active dummy circuit that is controlled by this second control signal and consumes a current larger than the current that makes the pulse load supply on the main output side unstable, and is active when the drive switch is operating. A power supply system for a motor, characterized in that a dummy circuit is operated, and an active dummy circuit is stopped when a drive switch is in a stopped state.