JPH03220916A - Semiconductor integrated circuit - Google Patents

Abstract

PURPOSE:To surely and simply control the stop of conversion operation and its release of a D/A converter section by inserting a circuit controlling passing of a current with a control signal between a transistor(TR) and a D/A converter or in the inside of the D/A converter. CONSTITUTION:A circuit 5 controlling passing of a current with a control signal 6 is inserted between a transistor(TR) 3 and a D/A converter 1 or in the inside of the D/A converter 1. The control signal applied to the terminal 6 controls the circuit 5 controlling passing of the current. That is, the single control signal fed from the terminal 6 is used to control the circuit 5, thereby interrupting the continuity between an inverter and the D/A converter 1 to stop the operation of the D/A converter 1 independently of the application of the digital signal. Thus, the operation stop state of the D/A converter 1 is obtained regardless of the setting of the digital signal with respect to the D/A converter 1 and the single signal required for the state setting is enough, then the semiconductor integrated circuit is simply and surely operated.

Description

[Detailed description of the invention] [v1 required] Regarding a semiconductor integrated circuit that can control the operation of a complementary MOS device and a D/A converter, a semiconductor integrated circuit that connects the complementary MOS device and the D/A converter. The purpose of the present invention is to provide a semiconductor integrated circuit that can simply and reliably control the stopping and canceling of the conversion operation of the D/A converter section by inserting a control circuit, In a semiconductor integrated circuit that controls the operation of a converter, a circuit that controls current passage using a control signal is inserted between the transistor and the D/A converter or inside the D/A converter.

[Industrial Field of Application] The present invention relates to a semiconductor integrated circuit that can control the operations of complementary MOS devices and D/A converters.

Conventionally, in a circuit that connects a complementary MOS device and a D/A converter, when stopping the operation of the D/A converter, an operation stop signal is applied from the input side of the complementary MO3) transistor. There was a need. It was desired to obtain a circuit configuration that would simply and reliably prevent the D/A converter from operating.

[Conventional technology] FIG. 6 is a diagram showing a conventional C-MO3 circuit.

In FIG. 6, 1 is a known D/A converter in which elements with resistance values R and 2R are connected in a ladder type, and 2-0 to 2
-n is an application terminal for digital signals D0 to Dn, 3-0 to
3-n is a two-stage C-MO3 type inverter, and 4 is an analog signal output terminal. If an n-bit digital signal is applied to the digital signal application terminal 2 and the inverter 3 is made conductive in response to the "H" level of the digital signal,
D/A converter 1 in which the current flowing through the resistance element changes
As a result, the output converted to an analog value can be taken out from the terminal 4.

Digital signal application terminals D0 to D indicated as 2-〇 to 2-n
The output of the converted analog signal is stabilized only when an It L w or "H" signal is applied to n. Further, these circuits including the inverter 3 may be formed on the same substrate along with other circuits using C-MOS manufacturing technology and shipped. In that case, the power supply VDD+ of the inverter section when the D/A converter is operating normally
The current from s is measured and used as data for determining the quality of the circuit.

Now, when "H" is applied to the terminal and the state is stable,
The upper P-channel FET of the second stage of inverter 3 becomes conductive, and current flows from VDD to ground.

Next, when "L" is applied to the terminal and the state becomes stable,
The second stage N-channel FET of inverter 3 becomes conductive.

[Problems to be Solved by the Invention] In the circuit shown in FIG. 6, it is necessary to apply an "L" signal to the digital signal application terminal 2 in order to measure the current when the power is reduced. If other circuits were present in the preceding stage, the signal could not be stabilized simply by applying an "L" signal to the terminal pin, and measurement could not be performed as it was.

An object of the present invention is to improve the above-mentioned drawbacks, and to provide a control circuit for stopping and canceling the conversion operation of the D/A converter in a semiconductor integrated circuit that connects a complementary MOS device and a D/A converter. It is an object of the present invention to provide a semiconductor integrated circuit that can be inserted and controlled simply and reliably.

[Means for Solving the Problems] FIG. 1 is a diagram showing the basic configuration of the present invention. In FIG. 1, 1 is a D/A converter, 2-0 to 2-n are application terminals for digital signals D0 to Dn, and 3-0 to 3-n are complementary M
In the OS device, 4 is an analog signal output terminal, 5 is a circuit for controlling current passage, and 6 is a control signal application terminal.

The present invention has the following configuration in a semiconductor integrated circuit that controls the internal operation of a D/A converter connected to the complementary MO3 type device 3. That is, a circuit 5 for controlling current passage using a control signal 6 is inserted between the transistor 3 and the D/A converter or inside the D/A converter 1.

FIG. 2 shows the circuit 5 for controlling the passage of current in FIG.
The case where it is inserted inside the /A conversion converter is shown.

[Operation] In FIG. 1, a signal applied from the terminal 6 performs a control operation in the circuit 5 that controls the passage of current.

That is, if conduction between the inverter and the D/A converter 1 in the circuit 5 is turned off by a single control signal from the terminal 6, the D/A converter 1 is turned off regardless of the application of the digital signal.
operation stops. Therefore, the state at the time of a predetermined power drop can be easily determined.

The operation in FIG. 2 is similar to that in FIG.

[Embodiment] FIGS. 3 and 4 show an embodiment circuit diagram for FIG. 1, and FIG. 5 shows an embodiment circuit diagram for FIG. 2.

FIG. 3 shows a case where an ant circuit 7 is used as the control circuit 5, and 7-0 to 7-n indicate the AND circuits.

When operating the D/A converter 1 normally, an "H" level signal is applied from the control signal application terminal 6.

The signal is a digital signal applied to the terminal 2 and is inputted to the D/A converter 1 via the AND circuit 7.

If the signal terminal 6 is set to the "L" level, the signal from the digital signal terminal 2 cannot pass through the AND circuit 7.

As a result, the D/A converter 1 becomes inactive, and by measuring the current on the power supply side, the value at the time of power reduction can be obtained.

FIG. 4 shows an example in which an electronic switch 8 is used as the control circuit 5. If P-channel and N-channel FETs are connected back to back and a control signal of "L" and "H" is applied, the switch can be switched. Operates as a power-down current measurement with the switch off.

FIG. 5 is a diagram showing a case where a switch as shown in FIG. 4 is inserted inside a D/A converter. If you measure the current with the switch off, you will get the value when the power drops.

[Effects of the Invention] In this way, according to the present invention, it is possible to obtain a state in which the operation of the D/A converter is stopped without depending on the settings of digital signals for the D/A converter. Moreover, since only a single signal is required for setting the state, the semiconductor integrated circuit can be operated easily and reliably.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the principle configuration of the present invention, FIG. 2 is a diagram showing a modified circuit of FIG. 1, FIGS. 3 to 5 are diagrams showing the configuration of an embodiment of the present invention, and FIG.
The figure shows a conventional C-MOS circuit. D/A converter Digital signal application terminal Complementary MOS device Analog signal output terminal Circuit that controls current passage Single signal application terminal

Claims (1)

[Claims] In a semiconductor integrated circuit that controls the operation of a D/A converter (1) connected to a complementary MOS device (3), a circuit (5) that controls current passage by a control signal (6) is connected to the complementary MOS device (3). A semiconductor integrated circuit characterized by being inserted between a device (3) and a D/A converter (1) or inside the D/A converter (1).