Patent ID: 11870236
Assignee: ROHM CO., LTD.
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H  B  G | IPC B  G  H

Claim 0:
1. An overcurrent protection circuit comprising:
a current controller configured to control a transistor to limit a flowing output current to a predetermined upper limit or less while keeping the transistor turned on; and
a duty controller configured to turn on/off the transistor at a predetermined duty ratio when a temperature protection circuit detects a temperature abnormality,
wherein the current controller is further configured to:
compare a sense voltage corresponding to the output current with a threshold voltage corresponding to the predetermined upper limit; and
generate a first overcurrent protection signal configured to control the the transistor and a state notification signal configured to notify the duty controller of a state where the current controller limits the output current,

wherein the duty controller includes:
a latch configured to switch and hold a pulse generation control signal from a logic level at the time of disabling to a logic level at the time of enabling when the state notification signal is at a logic level at the time of current limitation and a temperature protection signal is at a logic level at the time of abnormality detection;
a pulse signal generator configured to generate a pulse signal having the duty ratio while the pulse generation control signal is at the logic level at the time of enabling; and
a level shifter configured to generate a second overcurrent protection signal configured to turn on/off the transistor at the duty ratio by level-shifting the pulse signal.