Regulator circuit
The present invention is contrived to adopt a differential pair type amplifier circuit comprising a differential pair constituted by a first transistor receiving an input of a first signal and by a second transistor receiving an input of a third signal generated by outputting a second signal of which the voltage level is a power supply voltage. Elements requiring a matching are two transistors constituting the differential pair for the amplifier circuit. Because of this, the elements requiring a matching can be placed close to each other regardless of a layout between the amplifier circuits.
1. A regulator circuit comprising:
a load driving amplifier including a differential pair and configured to output a second signal of a constant power supply voltage and supply a load current through a first output node of the load driving amplifier, the differential pair including a first transistor configured to receive an input of a first signal used as a reference and a second transistor configured to receive an input of a third signal generated on the basis of the second signal the first signal being a signal of a bandgap voltage;
a resistance voltage division circuit configured to generate the third signal from the second signal; and
a charging-use amplifier configured to charge a capacitance element through a second output node of the charging-use amplifier in a time period during which the load driving amplifier is in an off state, the capacitance element and the second output node of the charging-use amplifier being electrically connected to the first output node of the load driving amplifier.
2. The regulator circuit according to claim 1 , further comprising
an output stopping unit configured to stop an output of the second signal from the load driving amplifier during the time period in which the charging-use amplifier charges the capacitance element.
3. The regulator circuit according to claim 2 , wherein the time period is one immediately after turning electric power on.
4. The regulator circuit according to claim 1 , wherein
the charging-use amplifier comprises an electric current control unit for controlling an electric current flowing in the second transistor, in addition to substantially the same configuration as the load driving amplifier.
5. The regulator circuit according to claim 4 , wherein
the electric current control unit suppresses an increase of an electric current flowing in the second transistor with voltage applied thereto.
6. The regulator circuit according to claim 1 , further comprising
a discharge unit configured to respond to an over-charging in the capacitance element by making the capacitance element discharge a charged charge therein after completing a charging by the charging-use amplifier.
7. The regulator circuit according to claim 1 , wherein the load driving amplifier comprises a current source for making a sum of currents supplied by the differential pair constant.
8. The regulator circuit according to claim 1 , wherein
an amount of an electric current supplied by the charging-use amplifier is smaller than an amount of an electric current supplied by the load driving amplifier.