rt9212 Richtek Technology Corporation, rt9212 Datasheet - Page 4

• Manufacturer Part Number: rt9212
• Description: Dual Synchronous Buck Dc-dc Linear Power Controller
• Manufacturer: Richtek Technology Corporation

PGOOD (Pin 19)
PGOOD is an open-drain output used to indicate that both
the channel 1 and channel 2 regulators are within normal
operating voltage ranges.
OCSET2/SD (Pin 20), OCSET1/SD (Pin 21)
Connect a resistor (R
the upper MOSFET of the supply voltage sets the over-
current trip point. R
, and the upper MOSFET on-resistance, (R
converter over-current trip point (I
following equation:
An over-current trip cycles the soft-start function. Pulling
the pin to ground resets the device and all external
MOSFETs are turned off allowing the two output voltage
power rails to float.
Function Block Diagram
www.richtek.com
4
RT9212
I
OCSET
=
PGOOD
R
COMP1
DS(ON)
VCC
DRV
FB1
FB2
FBL
OCSET
OCSET
40uA
of
, an internal 40μA current source
the
) from this pin to the drain of
Power
Good
×
upper
R
OCSET
Regulator
OCSET
Linear
0.8V
0.8V
Ref.
MOSFET
) according to the
Zf
137.5%
62.5%
DS(ON)
FB2
, set the
+
+
-
-
OVP
UVP
EA
EA
Zc
&
+
Preliminary
+
OV
UV
GNDA
Oscillator
300kHz
180 deg
shift
Power
Reset
PVCC1 (Pin 22)
Connect this pin to a well-decoupled 5V supply. It is also
the positive supply for the lower gate driver, LGATE1.
LGATE1 (Pin 23)
Channel 1 power gate drive output. Connect to gate of the
low-side power N-Channel MOSFET. This pin is monitored
by the adaptive shoot-through protection circuitry to
determine when the lower MOSFET has turned off.
PGND1 (Pin 24)
Return pin for high currents flowing in low-side power
N-MOSFET. Ties the pin directly to the low-side MOSFET
source and ground plane with the lowest impedance.
on
+
-
-
+
Thermal
Thermal
SHDN
SHDN
PWM1
POR
PWM2
OV
UV
UV
OC
OV
OC
OV
UV
POR
Soft-
Start
2
Bias
Control
Control
Soft-
Start
Logic
Logic
1
OC
Thermal
OC
SHDN
VCC
+
-
+
-
40uA
40uA
OCSET1/SD
BOOT1
UGATE1
PHASE1
PVCC1
LGATE1
PGND1
PGND2
LGATE2
PHASE2
UGATE2
BOOT2
OCSET2/SD
DS9212-05 March 2007