PIN

NAME

DESCRIPTION

APPLICATIONS INFORMATION

8

GND1

Ground, Controller 1

Ground connection for Controller 1 including gate driver, PWM

controller, soft-start and support functions.

9

GND2

Ground, Controller 2

Ground connection for Controller 2 including the gate driver, PWM

controller and soft-start.

10

OUT2

Main Gate Driver, Controller 2

Gate driver output to the primary side switch for Controller 2. OUT2

swings between VCC and GND2 at a frequency equal to half the

oscillator frequency.

11

RES

Hiccup mode restart adjust

An external capacitor sets the time delay before forced restart during a

sustained period of cycle-by-cycle current limiting. The hiccup mode

comparator threshold is 2.55V.

12

SS2

Soft-start, Controller 2

An internal 50 µA current source charges an external capacitor to set

the soft-start rate. During a current limit restart sequence, the internal

current source is reduced to 1µA to increase the delay before retry.

Forcing SS2 below 0.5V shuts off Controller 2.

13

CS2

Current Sense Input, Controller 2

Input for current mode control and the current limit sensing. If the CS2

pin exceeds 0.5V the OUT2 pulse is terminated producing

cycle-by-cycle current limiting. External resistance connected to CS2

will adjust (increase) PWM slope compensation. This pin’s voltage

must not exceed 1.25V.

14

COMP2

PWM Control, Controller 2

The COMP2 input provides voltage feedback to the PWM comparator

inverting input of Controller 2 through a 3:1 divider. The OUT2 duty

cycle increases as the COMP2 voltage increases. An internal 5k

Ω

pull-up resistor to +5.0V provides bias current to the opto-coupler

transistor.

15

DCL

Duty Cycle Limit

An external resistor sets the maximum allowed duty cycle at OUT1

and OUT2.

16

RT/SYNC Oscillator Adjust and

Synchronizing input

An external resistor sets the oscillator frequency. This pin also accepts

ac-coupled synchronization pulses from an external source.

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