Patent ID: 10803961

Abstract:
A comparator (13) compares a pad voltage with a reference voltage (Vref1) to output a voltage (VCCOK), and a comparator (23) compares a low voltage with a reference voltage (Vref2) to output a voltage (VDDOK). A power-on circuit (2) includes a timer circuit (11) and starts a reference voltage generation circuit (12) after the power switch control circuit is started, and then starts the comparator (13). After the comparator (13) is started, a controller (30) starts a voltage down converter (4) when the voltage (VCCOK) is at the H level, and turns on a MOS transistor (Q1) when the voltage (VCCOK) is at the L level. A power-on circuit (3) includes a timer circuit (21) and starts a reference voltage generation circuit (22) after the voltage down converter (4) is started, and then starts a comparator (23). After the comparator (23) is started, the controller (30) enters the standby state.