Patent ID: 8817432

Claim:
A driver circuit for driving a core circuit, the driver circuit comprising: a pad for receiving a pad voltage signal; a trace high circuit having a first input terminal coupled to the pad for receiving the pad voltage signal, the trace high circuit further having a second input terminal for receiving a power supply voltage, and an output terminal for outputting a trace high voltage approximating a higher voltage of the pad voltage signal and the power supply voltage; a level shifter having a first input terminal coupled to the output terminal of the trace high circuit for receiving the trace high voltage, a second input terminal for receiving a programming control signal, and an output terminal for outputting a level-shifted programming control signal generated by level shifting the programming control signal according to the trace high voltage; a first inverter having a first input terminal coupled to the trace high circuit for receiving the trace high voltage, a second input terminal coupled to the output terminal of the level shifter, and an output terminal for outputting a pull high control signal generated by inverting the level-shifted programming control signal; an ESD blocking circuit coupled to the level shifter, the pad, and the core circuit, the ESD blocking circuit comprising: a first transistor comprising: an input terminal coupled to the pad for receiving the pad voltage signal; an output terminal; and a control terminal for receiving the level-shifted programming control signal, the control terminal controlling the ESD blocking circuit to block the pad voltage signal from reaching the core circuit when the pad voltage signal is not for programming, and to allow the pad voltage signal to reach the core circuit when the pad voltage signal is for programming; and a pull high circuit coupled to the first inverter and the core circuit for receiving the pull high control signal and the power supply voltage, and outputting the power supply voltage to the core circuit when the pull high control signal is lower than the power supply voltage.