RT8113 Просмотр технического описания (PDF) - Richtek Technology

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RT8113

Single Phase VR11.1 PWM Controller with 7-bit VID

Richtek Technology 

RT8113

After VOUT ramps to VBOOT, the RT8113 stays in this state

for 800μs (tD3) waiting for valid VID code sent by CPU.

After receiving valid VID code, VOUT continues ramping up

or down to the voltage specified by VID code. After VOUT

ramps to VEAP = VDAC − VADJ, the RT8113 stays in this

state for 1600μs (tD5) and then asserts PGOOD = high.

The ramping slew rate of tD2 and tD4 is controlled by the

external capacitor connected to SS pin. The voltage of

the SS pin will always be VEAP+0.7V, where the mentioned

0.7V is the typical turn-on threshold of an internal power

switch. Before PGOOD = high, the slew rate of VEAP is

limited to 16μA/CSS. When PGOOD = high, the slew rate

of VEAP is limited to 160μA/CSS, which is 10 times faster

than soft start slew rate for dynamic VID feature. The soft

start waveform is shown in Figure 4.

C2

C3 R3 C1 R2

R1

VOUT

Soft Start Current (ISS)

is Limited and Variant

VDAC

Soft Start

Circuit

FB

COMP

-

EA

+

EAP

(Error AMP Positive Input)

ISS

SS

ADJ

CSS

RADJ

Figure 3. Circuit for Soft-Start and Dynamic VID

VCC5

VCC12

VDAC

4.6V

9.6V

PGOOD

tD1

tD2

tD3

tD4

tD5

Figure 4. Soft-Start Wave forms

SS

VOUT

VBOOT

DS8113-02 April 2011

www.richtek.com

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