Power supply circuit

Abstract

The present invention relates to a power supply circuit used in devices using various batteries such as mobile phones, and more particularly to a power supply circuit capable of reducing power consumption. When the CPU 11 is in normal operation, the DC-DC transformer 2 is used to efficiently step down the power supply voltage VDD to the voltage Va, and then the voltage regulator 3 is used to step down to obtain a stable voltage Vb, which is supplied to the CPU 11; if the CPU 11 is in a standby state, the DC - The DC transformer 2 becomes inactive, stops its operation, and suppresses power consumption. At the same time, only the voltage regulator 3 adjusts the power supply voltage VDD passed through the DC-DC transformer 2 to a desired voltage Vb, and supplies it to the CPU 11 . The power supply circuit of the present invention can reduce power consumption in a standby state, and at the same time, even when a device to be supplied with power is intermittently operated in the standby state, power can be supplied to the device.

Description

technical field [0001] The present invention relates to a power supply circuit used in devices using various types of batteries, such as mobile phones, and more particularly to a power supply circuit capable of realizing low power consumption. Background technique [0002] Conventionally, a voltage regulator and a DC-DC transformer have been used as a power supply circuit for stepping down a DC voltage supplied from a DC power supply to a predetermined voltage. [0003] Figure 14 It is a circuit diagram of a known technical example of a power supply circuit using a voltage regulator. exist Figure 14 In the voltage regulator 100, P-channel type MOS transistors (hereinafter abbreviated as "PMOS transistors") are connected in series between the power supply terminal to which the power supply voltage VDD is applied from a DC power supply 101 such as various batteries (including secondary batteries) and the ground. ) 102, resistors 103 and 104. [0004...

AI Technical Summary

Problems solved by technology

When the DC-DC converter 110 is used in the always active state, the power consumption of the DC-DC converter 110 itself has a great influence on the power consumption of the device

In addition, in a device that uses a battery as a power source, it is necessary to reduce power consumption as much as possible to suppress battery consumption. If the DC-DC transformer 110 is replaced with a voltage regulator that consumes a lot of power, there is a problem of large power consumption.

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