Power conversion integrated circuit and method for programming

A semiconductor chip having at least four external electrical connections, comprising:

• an internal regulator;
• a state circuit having an output coupled to a control input of the internal regulator;
• a first electrical connection terminal for coupling an external ground reference to an internal ground reference of the internal regulator;
• a second electrical connection terminal for providing a pulse-width modulated output signal from an output of the internal regulator;
• a third electrical connection terminal coupled for receiving a feedback signal at an input of the internal regulator to control the pulse-width modulated output signal;
• and
• a fourth electrical connection terminal coupled for receiving a control signal which is applied to the state circuit to set a mode of operation of the internal regulator.

A programmable power supply, comprising:

• a transformer receiving a rectified signal at a primary side of the transformer;
• a state circuit having an input and an output for setting a mode of operation of the programmable power supply, wherein the state circuit includes,
• a comparator circuit having a first input coupled to the input of the state circuit for receiving a control signal and a second input coupled for receiving a first reference signal, and
• a memory circuit having a first input coupled to an output of the comparator for setting an output state of the memory circuit according to a value of the control signal where the output state of the memory circuit controls the mode of operation;
• a control circuit coupled for receiving the output state of the memory circuit and wherein the control circuit is responsive to a feedback signal for providing a pulse-width modulated control signal;
• and
• a transistor having a control terminal for receiving the pulse-width modulated control signal, a first conduction terminal coupled to the primary side of the transformer, and a second conduction terminal coupled to ground.