INPUT FRONT-END CIRCUIT FOR SWITCHING POWER SUPPLY CONTROL INTEGRATED CIRCUIT AND SWITCHING POWER SUPPLY CONTROLLER HAVING THE SAME

摘要

An inverting amplifier creates a voltage C using a reference voltage (voltage B) as a reference point. An adder composed of two input inverting amplifier circuits ultimately creates a voltage D by carrying out weighted addition of the voltage A and the voltage C. By using the voltage D created by an input front-end circuit, the internal functions of the control IC can prevent the operating points and control amounts for each function from being different relative to the input voltage and make it possible to distinguish voltage within the control IC from zero voltage when the lowest input voltage is received.

主权项

1. An input front-end circuit for a switching power supply control integrated circuit, comprising:
a first inverting amplifier that receives a first voltage originating from an input voltage at an input and that receives a first reference voltage at a reference input so as to generate an inverted and amplified voltage as a second voltage; an adder comprising a second inverting amplifier that receives the first voltage at a first input, the second voltage at a second input, and a second reference voltage at a reference input so as to output a resulting added, inverted, and amplified signal to one or more components within the switching power-supply control integrated circuit.