JPH01293413A - Reference voltage generating circuit - Google Patents

Abstract

PURPOSE:To easily realize the control, etc., of an output voltage due to the external control, long-term stability and temperature of a generation voltage by outputting a reference voltage obtained at respective reference voltage output terminals. CONSTITUTION:A timing generating circuit 5 outputs respective pulses (d) and (e) to the position corresponding to an address signal (g) for sample-and-hold circuits 3 and 4. By the timing of the pulses (d) and (d), the sample-and-hold circuits 3 and 4 fixes an analog output signal (e) which is an input signal respectively and outputs stably reference voltages Vc1f and Vc2g to reference voltage output terminals 6 and 7. Thus, the control, etc., of the output voltage due to the external control, long-term stability and temperature of the generation voltage can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates generally to devices having electronic circuits, and particularly to a reference voltage generating circuit that requires initial setting.

BACKGROUND ART An example of a conventional reference voltage generating circuit is shown in FIG. 3 and will be described.

In the figure, reference numerals 11 and 12 are voltage source connection terminals, 13 is a reference voltage output terminal from which a reference potential ve can be obtained, and 14 is a variable resistor. Use by connecting a grounding circuit.

Then, the potentials of the voltage source connection terminals 11 and 12 are set to V
a and Vb, the reference potential Ve obtained at the reference voltage output terminal 13 can be set to a value between the potential V and the potential vb depending on the setting position of the slider of the variable resistor 14.

[Problem to be solved by the invention]

In the conventional reference voltage generation circuit using the variable resistor described above, the reference potential vc to be initially set is determined by the mechanically fixed position of the slider of the variable resistor.

Therefore, the reference potential vI! from the outside of the electronic device having this reference voltage generation circuit! It is difficult to adjust, and it becomes even more difficult when automatic adjustment is performed by a machine. In addition, in order to keep the reference potential c stable over the long term, it is essential that the contact between the electrical contact surfaces of the slider is physically stable. Requires complicated treatment. Furthermore, it is difficult to realize a complex function such as changing the reference potential VC itself in accordance with changes in the environmental temperature with a reference voltage generating circuit that is made up of all variable resistors.

As described above, in the conventional reference voltage generation circuit, external control of the generated voltage, long-term stability, and the change of output '1 pressure due to temperature
I have rarely encountered a problem in which it is extremely difficult to achieve the LJ control.

[Means of rounding to solve problems]

According to the standard of the present invention, a pressure generating circuit includes a ROM that stores voltage data, a D/A converter that converts the output data of this ROM into an analog voltage, and a voltage that samples the output of this D/A converter and fixes it. This circuit has a sample and hold circuit that outputs a sample and a timing signal, and a timing generation circuit that generates an address signal for the upper Y ROM and a sampling signal for the sample and hold circuit.

[Effect]

In the present invention, a desired reference voltage is output to each reference voltage output terminal.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 is a block diagram showing one embodiment of a reference voltage generating circuit according to the present invention.

In the figure, 1 is a ROM that stores voltage data.

2 is a D/A converter that converts the output data of this ROM 1 into analog voltage, and 3 and 4 are this sim converter 2.
5 is a timing generation circuit that generates the address signal of the ROM 1 and the sampling signal of the sample and hold circuits 3 and 4.

The reference voltage output terminals 6 and 7 are configured to output the reference voltage Vex I Vc z to be obtained, respectively.

FIG. 2 is a time chart of signals of various parts of the reference voltage generation circuit of FIG. 1.

Next, the operation of the embodiment shown in FIG. 1 will be explained with reference to FIG. 2.

First, (&) in FIG. 2 is the address signal 8% outputted from the timing generation circuit 5 to ROM 1 (b) is the output data signal from the ROMI corresponding to this address signal a (F), D The data to be sent to converter 2 is stored in /. Incidentally, normally both of the address signal a1 and the output data signal are a plurality of parallel signals. And D
The /A converter 2 uses this output data 100 as a digital input to obtain an analog output signal C (see FIG. 2(e)). This analog output signal C is set to a reference voltage vc1 according to the address signal a as shown in FIG.
and the reference voltage vc! Repeat the voltage with the value of .

Next, the timing generation circuit 5 generates each pulse d, e (Fig. 2(d), (
(see e)) is output to the position corresponding to address signal a. Then, at the timing of these pulses d and e, the sample
Hold circuits 3 and 4 each have an input! ! The analog output No. 1d C is fixed and the reference voltage output terminal 6. The reference voltages Vc 1 (f) and V c t (g) are stably output at the terminals T (see FIGS. 2(f) and (g)).

Although the case of two outputs has been explained in FIGS. 1 and 2 as an example, the present invention is not limited to this, and even in cases other than two outputs, the data stored in the ROM 1 and the timing generation circuit 5 This can be done by simply changing the output of and the number of sample 1 hold circuits.

In addition, the long-term stability of the output voltage is determined by the stability of the Habo D/A converter and sample-and-hold circuit, and since the D/A converter and sample-and-hold circuit have no mechanically moving parts, they are extremely stable. A reference voltage output is obtained. 9. During the initial setting, the output voltage t-
If you want to control it, you can pull out the ROM part with an electric cable and connect it to a control device that has the same functions as the ROM, except that you can freely change the data. The initial setting of the reference voltage output can be remotely controlled electrically. After completing this adjustment, l! II
The data of the adjustment result may be stored in a ROM and the ROM may be mounted on the reference voltage generation circuit again.

Furthermore, it is possible to change the reference voltage output depending on the environmental temperature by adding data stored in the ROM and changing the address signal from the timing generation circuit depending on the temperature.

〔Effect of the invention〕

As explained above, the present invention includes a ROM that stores voltage data, a D/A converter that converts the output data of this ROM into an analog voltage, and a fixed voltage that is output by sampling the output of this D/A converter. sample/
By providing a hold circuit and a timing generation circuit that generates the address signal for the ROM and the sampling signal for the sample φ hold circuit, external control of the generated voltage, long-term stability, and temperature-dependent output voltage control are easily achieved. This has the advantage that it is possible to configure a reference voltage generation circuit that can be realized in a number of ways.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the reference voltage generating circuit according to the present invention, and FIG. 2 is a block diagram showing an embodiment of the reference voltage generating circuit according to the present invention. FIG. 1 is a time chart of signals of various parts of the reference voltage generation circuit, and FIG. 3 is a configuration diagram showing an example of a conventional reference voltage generation circuit. 1----- ROM, 2----- To D/-, converter, 3.4... fist pull φ hold circuit, 5.
...Timing generation circuit.

Claims (1)

[Claims] A ROM that stores voltage data, a D/A converter that converts the output data of this ROM into an analog voltage, a sample/hold circuit that samples the output of this D/A converter and outputs a fixed voltage, and the ROM. 1. A reference voltage generation circuit comprising: a timing generation circuit that generates an address signal for the sample-and-hold circuit and a sampling signal for the sample-and-hold circuit.