RT3612EB datasheet(31/47 Pages) RICHTEK

31 / 47 page

RT3612EB

DS3612EB-02 December 2019

www.richtek.com

is a registered trademark of Richtek Technology Corporation.

Adaptive Quick Response (AQR)

The RT3612EB features adaptive quick response (AQR)

function to optimize transient response. The mechanism

concept is illustrated in Figure 16. Controller detects

output voltage drop slew rate. While the slew rate exceeds

the AQR threshold, all PWMs turn on until output voltage

slew rate significantly slows down. The output voltage slew

rate transition also indicates that inductor current almost

reaches the loading current. Under such mechanism, AQR

PWM width is adaptive to variable loading step. The

RT3612EB provides various AQR threshold through PIN-

SETTING of AQR_TH[2:0]. The following equation can

initially decide the AQR starting trigger threshold. Smaller

threshold indicates larger AQR PWM. Note that the

threshold should be larger than steady-state output voltage

ripple falling slew rate and also the overshoot falling slew

rate to avoid miss triggering AQR.

dVSEN

AQR starting trigger threshold = -200k 20p



Figure 16. Adaptive Quick Response Mechanism

Output

voltage

VBIAS

AQR

Threshold

Vdiff

PWM_

AQR

PWM

_AQR

Output

voltage

AQR

Threshold

Vdiff

Table 10. PIN-SETTING of AQR_TH

AQR_TH[2:0]

AQR Starting Trigger

Threshold(mV)

000

440

001

520

010

600

011

680

100

760

101

840

110

920

111

Disable

Anti-overshoot (ANTI-OVS)

The RT3612EB provides Anti-overshoot Function to

depress output voltage overshoot. Controller detects

overshoot by signals relating to output voltage. The

overshoot trigger level can be adjusted by PIN-SETTING

as listed in Table 11. The main detecting signal comes

from COMP. However, COMP varies with compensation.

Initial trigger level setting can be based on the following

equation :

EA2

EA1

Antiovershoot Threshol

COMP

VSEN

d of ANTIOVS_TH[2 ]

  





The final setting should be according to actual Error AMP

compensator design and measurement.

While overshoot exceeds the setting trigger level, all

PWMs keep in tri-state until the zero current is detected.

Turning off LGs forces positive current flow through body

diode to cause diode forward voltage. The extra forward

voltage can speed up inductor current discharge and

decrease overshoot.

Table 11. PIN-SETTING of Anti-Overshoot Threshold

ANTIOVS_TH[2:0]

Anti-Overshoot Threshold

(mV)

000

001

120

010

150

011

180

100

210

101

240

110

270

111

Disable

RT3612EB Datasheet(PDF) 31 Page - Richtek Technology Corporation

RT3612EB Datasheet(HTML) 31 Page - Richtek Technology Corporation

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47

Datasheet Download

Link URL