DESCRIPTION
HA16116FP/FPJ and HA16121FP/FPJ are dual-channel PWM switching regulator controller ICs for use in chopper-type DC/DC converters. This logic assumes use of an N-channel power MOS FET for booster control, and a P-channel power MOS FET for step-down or inverting control. HA16116 includes a built-in logic circuit for step-down control only, and one for use in both step-down and inverting control. HA16121 has a logic circuit for booster control only and one for both step-down and inverting control. Both ICs have a pulse-by-pulse current limiter, which limits PWM pulse width per pulse as a means of protecting against overcurrent, and which uses an on/off timer for intermittent operation. Unlike conventional methods that use a latch timer for shutdown, when the pulse-by-pulse current limiter continues operation beyond the time set in the timer, the IC is made to operate intermittently (flickering operation), resulting in sharp vertical setting characteristics. When the overcurrent condition subsides, the output is automatically restored to normal.
Hitachi
