CPC G05F 1/571 (2013.01) | 22 Claims |
1. A voltage tracking circuit for tracking a first voltage at a first voltage terminal or a second voltage at a second voltage terminal to generate an output voltage, comprising:
a first P-type transistor having a gate, a drain, and a source, wherein the drain of the first P-type transistor is coupled to the first voltage terminal;
a second P-type transistor having a gate, a drain, and a source, wherein the gate of the second P-type transistor is coupled to the first voltage terminal, and the drain of the second P-type transistor is coupled to the second voltage terminal,
a driving circuit, coupled between the first voltage terminal and the gate of the first P-type transistor, generating a driving voltage according to the first voltage, wherein the driving circuit provides the driving voltage to the gate of the first P-type transistor; and
a control circuit, coupled to the first voltage terminal and the second voltage terminal, generating a control voltage according to the first voltage and the second voltage,
wherein the source of the first P-type transistor and the source of the second P-type transistor are coupled to an output terminal of the voltage tracking circuit, and the output voltage is generated at the output terminal, and
wherein in response to the second voltage being higher than the first voltage, the control circuit generates the control signal to turn off the first P-type transistor.
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