RT9229 Просмотр технического описания (PDF) - Richtek Technology

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RT9229

Advanced Dual PWM and Dual Linear Power Controller

Richtek Technology 

Functional Pin Description

UGATE1, UGATE2 (Pins 27 and 1)

Connect UGATE pins to the respective PWM

converter’s upper MOSFET gate. This pin provides

the gate drive for the upper MOSFETs.

PHASE1, PHASE2 (Pins 26 and 2)

Connect the PHASE pins to the PWM converter’s

upper MOSFET source. These pins are used to

monitor the voltage drop across the upper MOSFETs

for over-current protection.

VID0, VID1, VID2, VID3, VID4 (Pin 7, 6, 5, 4, and 3)

VID0~4 are the input pins to the 5-bit DAC. The

states of these five pins program the internal voltage

reference, DACOUT. The level of DACOUT sets the

core converter output voltage (VOUT1). It also sets

the core PGOOD and OVP thresholds. Table 1

specifies the DACOUT voltage of 32 combinations of

VID levels.

PGOOD (Pin 8)

PGOOD is an open collector output used to indicate

the status of the PWM converter output voltage. This

pin is pulled low when the core output is not within

±10% of the DACOUT reference voltage, or when

any of the other outputs are below their under-

voltage thresholds. The PGOOD output is open for

‘11111’VID code. See table 1.

FB1, FB2 (21 and 10)

FB1, 2 are the available external pins of the PWM

error amplifiers. Both the FB pins are the inverting

input of the error amplifiers.

OCSET1, OCSET2 (Pins 23 and 9)

Connect a resistor (ROCSET) from this pin to the drain

of the upper MOSFET. ROCSET, an internal 200µA

current source (IOCSET), and the upper MOSFET on-

resistance (RDS(ON)) set the converter over-current

(OC) trip point according to the following equation:

IPEAK =

IOCSET×ROCSET

RDS(ON)

RT9229

An over-current trip cycles the soft-start function.

Sustaining an over-current for 2 soft-start intervals

shuts down the controller.

SS (Pin 12)

Connect a capacitor from this pin to ground. This

capacitor, along with an internal 11µA (VSS>1V)

current source, sets the soft-start interval of the

converter.

Pulling this pin low with an open drain signal will shut

down the IC.

FAULT (Pin 13)

This pin is low during normal operation, but it is

pulled to about 8V (VCC = 12V) in the event of an

over-voltage or over-current condition.

FB4 (Pin 14)

Connect this pin to a resistor divider to set the linear

regulator output.

VSEN1, VSEN2 (Pins 22 and 15)

These pins are connected to the PWM converters’

output voltage. The PGOOD and OVP comparator

circuits use these signals to report output voltage

status and for over-voltage protection. VSEN2

provides the input power to the integrated linear

regulator.

DS9229-03 July 2001

www.richtek-ic.com.tw

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