Cantor Colburn LLP
Switching converter, control circuit thereof, AC/DC converter, power adapter and electronic device
A control circuit used in a switching converter having a coil, a switching transistor, and a detection resistor, includes: a current detection terminal configured to receive a detection voltage obtained by superimposing a voltage detection signal on a current detection signal; a sample hold circuit configured to sample-hold the detection voltage in an OFF period of the switching transistor to generate a sample hold voltage; a variable amplifier configured to amplify a difference between the sample hold voltage and the detection voltage; a duty controller configured to generate a pulse modulation signal; a driver configured to control the switching transistor based on the pulse modulation signal; and an overcurrent protection circuit configured to compare the detection voltage with a predetermined threshold voltage and change the pulse modulation signal to an OFF level of a switching transistor when the detection voltage is identical to the predetermined threshold voltage.
ROHM CO., LTD.
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Hiroki
Kikuchi