Preliminary
Function Block Diagram
VCC
RT9224E
VSEN
110%
Power-On
Reset (POR)
+
-
+
-
PGOOD
90%
115%
+
-
+
OCSET
-
Over Current
Reference
200uA
4.5V
Soft
Start
10uA
SS
BOOT
UGATE
Inhibit
Gate
Control
Logic
PHASE
Over Voltage
OVP
VID0
VID1
VID2
VID3
VID25
TTL D/A
Converter
(DAC)
DACOUT
Error Amplifier
+
-
PWM
Comparator
+
-
Oscillator
PWM
FB
LGATE
PGND
GND
DS9224E-02 March 2004
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3
RT9224E
Functional Pin Description
Pin No. Pin Name
1
VSEN
Pin Function
Preliminary
Output Voltage Monitoring Input for OVP and PGOOD
Over current set pin, sinks 200µA through a resistor (R
OCS
) from this upper N-MOSFET to
set the trip point:
2
OCSET
I
PEAK
=
200uA
×
R
OCS
MOSFET - on resistance
An over-current trip cycles the soft-start function
3
4
5
6
7
8
9,20
10
11
12
13
14
15
16
17
18
19
SS
VID25
VID0
VID1
VID2
VID3
NC
FB
GND
PGOOD
PHASE
UGATE
BOOT
PGND
LGATE
VCC
OVP
Soft start speed is set by internal 10µA current source and capacitor from this pin to GND
Switching regulator output voltage setting
Switching regulator output voltage setting
Switching regulator output voltage setting
Switching regulator output voltage setting
Switching regulator output voltage setting
No connection
Feedback input pin
IC signal ground
Open drain logic output
This pin is pulled low when the converter output is not within
±10%
of the DACOUT
reference voltage
Current limit sense input
High side driver output
Driver power
Low-side driver GND
Low side driver output
Power supply input
Over voltage protection
This pin is pulled high when the VSEN voltage is over 15% of the DACOUT reference
voltage
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DS9224E-02 March 2004
Preliminary
Table 1 Output Voltage Program
Pin Name
VID25
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
VID3
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
VID2
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
VID1
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
VID0
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
RT9224E
Nominal Output Voltage DACOUT
1.050V
1.075V
1.100V
1.125V
1.150V
1.175V
1.200V
1.225V
1.250V
1.275V
1.300V
1.325V
1.350V
1.375V
1.400V
1.425V
1.450V
1.475V
1.500V
1.525V
1.550V
1.575V
1.600V
1.625V
1.650V
1.675V
1.700V
1.725V
1.750V
1.775V
1.800V
1.825V
Note: (1) 0:Connected to GND (2) 1:Open
DS9224E-02 March 2004
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