DESCRIPTION
Utilizing a novel and unique design, the controller distributes the output load across (up to) four converter channels by digitally phase shifting the PWM outputs. Accurate current sharing among the four phases is achieved by precision design techniques and trimming of critical elements. The high speed transconductance error amplifier is externally initialized using a soft-start capacitor allowing the controller to “wake-up” without overshoot, thus protecting the low voltage microprocessor loads. The output drive voltage to the power MOSFETs is programmable to minimize switching losses in the drive circuitry. The output voltage is digitally programmable by means of a 5 bit DAC (new codes). A single resistor programs the master clock frequency (8MHz max) or the clock can be supplied by an external source where exact frequency control is desired. The number of operating phases is programmed independently of the external clock. The parts features under-voltage lock-out with hysteresis and over-current protection.
Semtech Corporation
