RT8223L datasheet(21/24 Pages) RICHTEK

21 / 24 page

RT8223L/M

DS8223L/M-04 April 2011

www.richtek.com

ENTRIPx or cycle VIN to reset the UVP fault latch and

restart the controller.

Thermal Protection

The RT8223L/M features thermal shutdown protection to

prevent overheat damage to the device. Thermal shutdown

occurs when the die temperature exceeds +150

°C. All

internal circuitry is inactive during thermal shutdown. The

RT8223L/M triggers thermal shutdown if VREGx is not

supplied from VOUTx, while the input voltage on VIN and

the drawing current from VREGx are too high. Even if

VREGx is supplied from VOUTx, large power dissipation

on automatic switches caused by overloading VREGx,

may also result in thermal shutdown.

Discharge Mode (Soft-Discharge)

When ENTRIPx is low and a transition to standby or

shutdown mode occurs, or the output under voltage fault

latch is set, the output discharge mode will be triggered.

During discharge mode, the output capacitors' residual

charge will be discharged to GND through an internal

switch.

Table 2. Operation Mode Truth Table

MODE

Condition

Comment

Power UP

VREGx < UVLO threshold

Transitions to discharge mode after a VIN POR and after

REF becomes valid. VREG5, VREG3, and REF remain

active.

RUN

EN = high, VOUT1 or VOUT2

enabled

Normal Operation.

Over Voltage

Protection

Either output > 111% of the nominal

level.

LGATEx is forced high. VREG3, VREG5 and REF active.

Exited by VIN POR or by toggling EN, ENTRIPx, ENC

Under

Voltage

Protection

Either output < 52% of the nominal

level after 3ms time-out expires and

output is enabled

Both UGATEx and LGATEx are forced low and enter

discharge mode. VREG3, VREG5 and REF are active.

Exited by VIN POR or by toggling EN, ENTRIPx, ENC

Discharge

Either SMPS output is still high in

either standby mode or shutdown

mode

During discharge mode, there is one path to discharge the

outputs capacitor residual charge. That is output capacitor

discharge to GND through an internal switch.

Standby

ENTRIPX<startup threshold, EN

=high.

VREG3, VREG5 and REF are active.

Shutdown

EN =low

All circuitry off.

Thermal

Shutdown

TJ > +150°C

All circuitry off. Exit by VIN POR or by toggling EN, ENTRIPx,

ENC

Shutdown Mode

The RT8223L/M SMPS1, SMPS2, VREG3 and VREG5

have independent enabling controls. Drive EN, ENTRIP1

and ENTRIP2 below the precise input falling-edge trip level

to place the RT8223L/M in its low power shutdown state.

The RT8223L/M consumes only 20

μA of input current while

in shutdown. When shutdown mode is activated, the

reference turns off. The accurate 0.4V falling-edge threshold

on the EN pin can be used to detect a specific analog

voltage level as well as to shutdown the device. Once in

shutdown, the 2.4V rising-edge threshold activates,

providing sufficient hysteresis for most applications.

Power Up Sequencing and On/Off Controls (ENC)

ENTRIP1 and ENTRIP2 control the SMPS power up

sequencing. When the RT8223L/M is in single channel

mode, ENTRIP1 or ENTRIP2 enables the respective output

when ENTRIPx voltage descends below 3V. Furthermore,

the RT8223M can also be in dual channel mode. In this

mode, outputs are enabled when ENC voltage rises above

2V.

RT8223L Datasheet(PDF) 21 Page - Richtek Technology Corporation

RT8223L Datasheet(HTML) 21 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

Datasheet Download

Link URL