JP2743804B2 - Reference voltage generation circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reference voltage generating circuit.

[0002]

2. Description of the Related Art A reference voltage can be generated by using a forward voltage drop of a diode or voltage division by a series resistor. For example, FIG. 2 shows an example of a reference voltage generating circuit using a diode, and a voltage obtained by flowing a steady current through the diode and appropriately amplifying using an amplifier is used as a reference voltage. Also illustrated in Figure 3 in which an example of a reference voltage generation circuit using a resistor divider, the electromotive force generated by the current flowing through the resistor, taking out from the appropriate node, any of the reference voltage by amplifying this with amplifiers Can be obtained.

[0003]

When a reference voltage is generated by such a means, it is necessary to constantly supply a current not only to the amplifier but also to a reference voltage generation section composed of a diode or a resistor. Was.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a reference voltage generating circuit which can eliminate a steady current consumption flowing in a portion for generating a reference voltage, reduce static power consumption, and generate an arbitrary reference voltage. And

[0005]

According to the present invention, a first positive theoretical switch for connecting between a first input terminal and a first output terminal and a connection between a second input terminal and a second output terminal are provided. A second positive theoretical switch, a negative theoretical switch that connects the first output terminal and the second input terminal, and a reference that includes a capacitor that connects the first output terminal and the second output terminal. Using n voltage generation elements (n ≧ 1), the first input and the second input of the i-th (i ≧ 2) reference voltage generation element
-1) connected to the first output and the second output of the reference voltage generating element, respectively,
And the second output are respectively connected to a first input and a second input of an (i + 1) th reference voltage generating element, and a second output terminal of the nth reference voltage generating element is grounded. A reference voltage generation unit configured by: a capacitor connecting a first input and a second input of the first reference voltage generation element;
A unit voltage source, a third positive theoretical switch connecting a high potential side of the unit voltage source and a first input of a first reference voltage generating element, a low potential side of the unit voltage source and the first potential switch, A fourth positive logic switch connecting a second input terminal of the reference voltage generation element, a first input terminal and a first output terminal of the first reference voltage generation element, and a second to n-th reference voltages A reference voltage generating circuit is constituted by a selector for selecting one from each of the first output terminals of the generating elements according to a desired reference voltage value, and an amplifier to which the output of the selector is input.
Here, the positive theoretical switch may be replaced with a negative theoretical switch, and the negative theoretical switch may be replaced with a positive theoretical switch.

By adopting such means, the reference voltage generator does not need a steady current as in the conventional example, so that static power consumption can be reduced and an arbitrary reference voltage can be generated.

[0007]

FIG. 1 shows an embodiment of a reference voltage generating circuit according to the present invention. In the figure, the positive theoretical switch and the negative theoretical switch are always exclusively controlled, and when one switch is in a conductive state, the other is in a non-conductive state. Switches of the same logic are controlled simultaneously.
First, when all the positive theoretical switches are turned on simultaneously, the unit voltage source 114 charges the capacitor 113 and the capacitors 108 of all the reference voltage generating elements in parallel. Thereafter, when all the positive theoretical switches are turned off and all the negative theoretical switches are turned on, the capacitance 113 and the capacitance of the first reference voltage generating element 110 to the capacitance 111 of the nth reference voltage generating element are connected in series. And one of the unit voltage sources 114
A voltage that is twice to (n + 1) times is supplied to the selector 117. The selector 117 selects one of the (n + 1) voltages in accordance with the selection input, is given to the amplifier 118, and its output becomes an available reference voltage. Since the unit voltage source only charges the capacity, static current consumption does not flow through the reference voltage generator 112. The electric charge charged to the capacitor is supplied to the amplifier 118 through a high input resistance element such as a MOSF.
By using ET, long-term retention is possible.

In addition to the embodiments described above, the present invention can be similarly applied to a case where an n-channel MOSFET and a p-channel MOSFET are used as the positive theoretical switch and the negative theoretical switch, respectively, or a combination of the opposite. Also, switch the complementary MOSF
The same effect can be obtained when the ET is used.

[0009]

As described above, according to the present invention, since a capacitance is used in the reference voltage generating section, static current consumption is not required for generating the reference voltage, and an arbitrary reference voltage can be generated. it can.

[Brief description of the drawings]

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

FIG. 2 is a diagram showing one embodiment of a conventional reference voltage generation circuit using a diode.

FIG. 3 is a diagram showing one embodiment of a conventional reference voltage generation circuit using resistance division.

[Explanation of symbols]

 101, 103 input terminal 102, 104 output terminal 105, 106, 115, 116 positive logic switch 107 negative logic switch 108, 113 capacitance 109, 110, 111 reference voltage generation element 112 reference voltage generation unit 114 unit voltage source 117 selector 118 amplifier

Claims (2)

(57) [Claims] A first positive logic switch connecting between a first input terminal and a first output terminal, a second input terminal and a second
A second positive logic switch connecting the output terminals of
N (n ≧ 1) reference voltage generating elements each including a negative theoretical switch connecting between the output terminal and the second input terminal and a capacitor connecting between the first output terminal and the second output terminal The first of the i-th (2 ≦ i ≦ n−1) reference voltage generation elements
And the second input are respectively connected to the first output and the second output of the (i-1) th reference voltage generating element, and the first output and the second output of the i-th reference voltage generating element are connected. Is connected to the first input and the second input of the (i + 1) th reference voltage generating element, respectively, and the second output terminal of the nth reference voltage generating element is grounded. A first input of a first reference voltage generating element and a second input of a first reference voltage generating element;
Of the capacitors connected between the input and the unit voltage source, a third positive theory switch for connecting the first input of the high potential side and the first reference voltage generation element unit voltage source, the unit voltage source A fourth positive theoretical switch that connects the low potential side to a second input terminal of the first reference voltage generation element, a first input terminal, a first output terminal, and a fourth output terminal of the first reference voltage generation element 2 to n
A selector for selecting one from a first output terminal of each of the reference voltage generating elements according to a desired reference voltage value;
A reference voltage generation circuit composed of an amplifier that receives the output of the selector as an input. 2. The reference voltage generating circuit according to claim 1, wherein the negative theoretical switch is replaced by a positive theoretical switch, and the first to fourth positive theoretical switches are replaced by negative theoretical switches.