RT8206A Просмотр технического описания (PDF) - Richtek Technology

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RT8206A

High Efficiency, Main Power Supply Controllers for Notebook Computers

Richtek Technology 

Functional Pin Description

REF (Pin 1)

2V Reference Output. Bypass to GND with a 0.22μF

capacitor. REF can source up to 50μA for external loads.

Loading REF degrades FBx and output accuracy according

to the REF load regulation error.

TON (Pin 2)

Frequency Select Input. (VOUT1/VOUT2 switching

frequency, respectively) :

TON = VCC, (200kHz / 250kHz)

TON = REF, (300kHz / 375kHz)

TON = GND, (400kHz / 500kHz)

VCC (Pin 3)

Analog Supply Voltage Input for the PWM Core. Bypass

to GND with a 1μF ceramic capacitor

ENLDO (Pin 4)

LDO Enable Input. The REF/LDO is enabled if ENLDO is

within logic high level and disable if ENLDO is less than

the logic low level.

NC (Pin 5, 8)

No Internal Connection.

VIN (Pin 6)

Power supply Input. VIN is used for the constant on-time

PWM one shot circuits. VIN is also used to power the

linear regulators. The linear regulators are powered by

SMPS1 if VOUT1 is set greater than 4.66V and BYP is

tied to VOUT1. Connect VIN to the battery input and

bypass with a 1μF capacitor.

LDO (Pin 7)

Linear Regulator Output. LDO can provide a total of 70mA

external loads. The LDO regulates a fixed 5V output. When

the BYP is within 5V switchover threshold, the internal

regulator shuts down and the LDO output pin connects to

BYP through a 1.5Ω switch. Bypass LDO output with a

minimum of 4.7μF ceramic.

BYP (Pin 9)

BYP is the switchover source voltage input for the LDO.

DS8206A/B-06 August 2011

RT8206A/B

VOUT1 (Pin 10)

SMPS1 Output Voltage Sense Input. Connect this pin to

the SMPS1 output. VOUT1 is an input to the Constant

on-time-PWM one-shot circuit. It also serves as the

SMPS1 feedback input in fixed voltage mode.

FB1 (Pin 11)

SMPS1 Feedback Input. Connect FB1 to VCC or GND for

fixed 5V operation. Connect FB1 to a resistive voltage

divider from VOUT1 to GND to adjust output from 2V to

5.5V.

ILIM1 (Pin 12)

SMPS1 Current Limit Adjustment. The GND − PHASE1

current limit threshold is 1/10th the voltage seen at ILIM1

over a 0.5V to 2V range. There is an internal 5μA current

source from VCC to ILIM1. The logic current limit threshold

is default to 100mV if ILIM1 is higher than (VCC − 1V).

PGOOD1 (Pin 13)

SMPS1 Power Good Open-Drain Output. PGOOD1 is low

when the SMPS1 output voltage is more than 7.5% below

the normal regulation point or during soft-start. PGOOD1

is high impedance when the output is in regulation and

the soft-start circuit has terminated. PGOOD1 is low in

shutdown.

EN1 (Pin 14)

SMPS1 Enable Input. The SMPS1 will be enabled if EN1

is greater than the logic high level and disabled if EN1 is

less than the logic low level. If EN1 is connected to REF,

the SMPS1 starts after the SMPS2 reaches regulation

(delay start). Drive EN1 below 0.8V to clear fault level and

reset the fault latches.

UGATE1 (Pin 15)

High Side MOSFET Floating Gate Driver Output for

SMPS1. UGATE1 swings between PHASE1 and BOOT1.

PHASE1 (Pin 16)

Inductor Connection for SMPS1. PHASE1 is the internal

lower supply rail for the UGATE1 high side gate driver.

PHASE1 is the current sense input for the SMPS1.

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