Switch-control integrated circuit

摘要

A switch-control integrated circuit for a switch-mode power supply (SMPS) capable of consistently limiting the peak current value of an output supply voltage irrespective of a temperature change. The circuit includes a switching transistor of the SMPS and a sensing resistor coupled to a drain of the switching transistor for sensing a drain current of the switching transistor to produce a peak current value detection voltage. A voltage generating circuit generates a feedback voltage which varies depending on the temperature condition equal to that of the sensing resistor. A comparator compares the temperature dependent voltage, received at a first input, with the temperature dependent peak current value detection voltage, received at a second input, to produce a temperature independent control signal. A protection circuit, coupled between the comparator and the switching transistor, interrupts the control signal if an abnormal operation of the voltage generating section is detected. Finally, a driving circuit drives the switching transistor in response to the control signal transmitted from the protection circuit.