JPS58219622A - Reference voltage generating circuit - Google Patents

Abstract

PURPOSE:To use parts in common and decrease the number of parts and to improve reliability, by selecting a specific output among respective outputs of reference voltage adjustment parts connected to a buffer on the basis of a specifying signal. CONSTITUTION:A voltage for a reference voltage developed across the voltage standardizing diode 12 in a reference voltage generation part 1 is led out, as it is, by the operational amplifier 21 of the buffer 2 and applied to reference voltage adjusting parts 31-3n, where it is adjusted by potention meters VR to requested voltages. The outputs of the adjustment parts 31-3n are applied to the photocouplers 71-73 of a reference voltage switching part 7 to output only a reference voltage applied to a photodetecting element corresponding to a light emitting element specified by a reference voltage selection signal SS to the buffer 5. The reference voltage applied to the buffer 5 is outputted, as it is, from an operational amplification part 51. Thus, the circuit part is used in common and unified, so the constitution is simplified.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reference voltage generation circuit that can obtain a plurality of reference voltages with a simple configuration.

As a conventional reference voltage generation circuit, for example, the one shown in FIG. 1 is used to generate stabilizing voltages of different values.

A reference voltage generating section 11 * 12 m...
. . 8, buffers 21 a 22 .
A reference voltage adjustment section 31 + 32...3n that is connected to the reference voltages 1 to 2n and applied to match the supplied reference voltage to the required voltage, and each of the reference voltage adjustment sections 31e, 32m, and so on. A reference voltage switching unit 4 that selects and outputs one of the outputs in accordance with an external command, a buffer 5 that buffers and amplifies the output of the reference voltage switching unit 4, and a reference voltage that receives the reference voltage selection signal S8 and selects and outputs the reference voltage. The reference voltage switching section 6 is configured to instruct the reference voltage switching section 4 as to which one is.

In the above configuration, each of the reference voltage generating sections 11 to 1n is set to generate a voltage higher than the required reference voltage, and each output is sent to the reference voltage adjusting sections 31 to 3 through the buffers 21 to 2n. .1, and this reference voltage adjustment section 3
Adjust the output voltage to the required reference voltage value for 1 to 3n. Since the voltage to be outputted from the reference voltage generating circuit is single, the reference 'rU4' and the voltage switching unit 4 select one of the reference voltage adjusting units 31 to 3n from the interface unit 6.
Only the designated reference voltage is selected and taken out to the outside via the buffer 5.

However, in the conventional reference voltage generating circuit, since a knockdown is provided for each of the reference voltage generating sections, the number of parts increases, the configuration becomes complicated, and reliability is poor.

The present invention has been made in view of the above, and provides a reference voltage generation circuit in which parts having the same structure are unified and parts that can be combined are integrated in order to simplify the structure. .

Below, the reference voltage generation circuit according to the present invention will be explained in detail. Explain.

FIG. 2 shows an embodiment of the invention, in which the same parts as in FIG. 1 are designated by the same reference numerals. In FIG. 2, the reference voltage generation circuit includes a reference voltage generation section 1 that outputs a stabilized voltage higher than the highest voltage among a plurality of required reference voltages, and a reference voltage generation section 1 that outputs a stabilized voltage higher than the highest voltage among a plurality of required reference voltages. An odd buffer 2 that buffers and amplifies the output voltage, a reference voltage adjustment section 31...3n that is connected in parallel to the buffer 2 and sets a plurality of required reference voltages, and the reference voltage. Adjustment part 3
The reference voltage selection signal S receives each output of 1...3n.
, and a buffer 5 that buffers and amplifies the reference voltage outputted from the reference voltage switching section 7. The reference voltage generation section 1 and the buffer 2 have the same configuration as shown in FIG. 1, and the reference voltage switching section 7 has the same configuration as the reference voltage switching section 4 and the interface section 6 shown in FIG. It has a function. The embodiment with the above configuration will be described in further detail.

FIG. 3 is a detailed circuit diagram of the embodiment of FIG. 2.

However, for convenience of explanation, a case where three types of reference voltages are created is shown. The reference voltage generator 1 includes a current limiting resistor 11 connected to a DC power supply Vcc, and a voltage standard diode 12 such as a Tsunner diode connected between the other end of the resistor 11 and ground. The buffer 2 is configured with an operational amplifier 21, and the voltage generated at the non-grounded terminal of the diode 12 is outputted as the reference voltage voltage. It is a high input impedance circuit with an output voltage applied to the negative input terminal, and outputs the reference voltage cloth and pressure without affecting the reference voltage generation section 1 as a load.Reference voltage adjustment sections 31 to 33 are all potentimeter V
R.

~VR, is used to lower the reference voltage voltage to the desired voltage and output it so that the reference voltage corresponding to the desired voltage is output from the buffer 5. ) The buffer 5 includes an operational amplifier 51 and a resistor 52, and uses the same circuit as the buffer 2 except that the resistor 52 is connected between the positive input terminal and ground. The reference voltage switching unit 7 includes photocouplers 71, 72, and 73, and resistors for limiting the current flowing through each of the light emitting elements of the couplers.
6, by making one of the light emitting elements conductive by the reference voltage selection signal S8, the conductive light emitting element emits light, and by turning on the paired light receiving element, one of the reference voltages is turned on. One is output to buffer 5.

In the above configuration, the reference voltage voltage generated at both terminals of the voltage standard diode 12 in the reference voltage generating section 1 is extracted as is by the operational amplifier 21 of the Nonotsufa-2, and the reference voltage adjusting sections 31 to 33 ( 3n) and is adjusted to the required voltage by a tension meter VR. Reference voltage adjustment section 3. - 33 are applied to the light-receiving elements of the photocouplers 71-73 of the reference voltage switching unit 7, and when the light-receiving element corresponding to the light-emitting element specified by the reference voltage selection signal S is turned on, the light-receiving element is switched on. Only the reference voltage applied to the element is output to the buffer 5. The buffer 5 outputs the applied reference voltage as it is to the operational amplifier 51.

In the embodiment shown in FIG. 3, a configuration is shown in which three types of reference voltages are obtained.
By adding potentiometers (or variable resistors) and photocouplers corresponding to the number of required reference voltages, it is possible to obtain an arbitrary number of reference voltages with different voltages.

Furthermore, in FIG. 3, the configuration is such that none of the buffers has an amplification degree, but it may be configured that they have an amplification degree.

As explained above, according to the reference voltage generating circuit of the present invention, the configuration can be simplified because the circuit parts are commonly used and integrated. This makes it possible to reduce the number of parts and improve reliability.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of a conventional reference voltage generation circuit, FIG. 2 is a block diagram showing an embodiment of the present invention, and FIG.
The figure is a detailed circuit diagram of the embodiment of FIG. 2. l...Reference voltage generation section, 2, 5, etc., 3
, ~3n... Reference voltage adjustment section, 7... Reference voltage switching section 2151 Figure 2E and j Figure 3

Claims (1)

[Scope of Claims] A reference voltage generation unit that generates a single level voltage that is stabilized at a constant level; a buffer that buffers and amplifies the W5 voltage of the reference voltage generation unit; and a voltage output from the Kupfer. A plurality of reference voltage adjustment sections are provided for each reference voltage in order to adjust the reference voltage to a plurality of required levels of reference voltage, and a plurality of reference voltage adjustment sections are provided for each reference voltage to adjust the reference voltage to a plurality of required levels of reference voltage, and a plurality of reference voltage adjustment sections are provided for each of the reference voltage adjustment sections. 1. A reference voltage generation circuit comprising: a reference voltage switching section that outputs only the reference voltage specified by the selected selection signal.