Automotive 4.1V to 15V, 1A push-pull current mode PWM controller

The UCC2808A-xQ1 is a family of BiCMOS

push-pull pulse-width modulators that are high-speed and low-power. The UCC2808A-xQ1

contains all of the control and drive circuitry required for off-line or DC-to-DC

fixed frequency current-mode switching power supplies with a minimal external part

count.

The UCC2808A-xQ1 dual output drive

stages are arranged in a push-pull configuration. Both outputs switch at half the

oscillator frequency using a toggle flip-flop. The dead time between the two outputs

is typically 60ns to 200ns, depending on the values of the timing capacitor and

resistors, thus limiting each output stage duty cycle to less than 50%.

The UCC2808A-xQ1 family offers a

variety of package options and choice of undervoltage lockout levels. The family has

UVLO thresholds and hysteresis options for off-line and battery powered systems.

Thresholds are shown in the orderable information table.

The UCC2808A-xQ1 is an enhanced

version of the UCC2808 family. The significant difference is that the A versions

feature an internal discharge transistor from the CS pin to ground, which is

activated each clock cycle during the oscillator dead time. The feature discharges

any filter capacitance on the CS pin during each cycle and helps minimize filter

capacitor values and current sense delay.