TPS40210-Q1, TPS40211-Q1
SLVS861D –AUGUST 2008–REVISED APRIL 2010
www.ti.com
VDD
8
V
IN
V
IN
Amplitude >
CLK
+
S
R
Q
Q
20
R
RC
Duty Cycle < 50%
RC
+
1
5
Frequency > Controller
Frequency
+
150 mV
C
RC
GND
TPS40210/11
UDG-08064
Figure 21. Diode Connected Synchronization
Current Sense and Overcurrent
The TPS40210 and TPS40211 are current-mode controllers and use a resistor in series with the source terminal
power FET to sense current for both the current-mode control and overcurrent protection. The device enters a
current-limit state if the voltage on the ISNS pin exceeds the current-limit threshold voltage VISNS(oc) from the
electrical specifications table. When this happens, the controller discharges the SS capacitor through a relatively
high impedance and then attempts to restart. The amount of output current that causes this to happen is
dependent on several variables in the converter.
V
TPS40210/11
10 VDD
IN
TPS40210/11
R
T
L
V
OUT
VDD 10
1
6
RC
C
T
GDRV
ISNS
8
7
GND
R
IFLT
UDG-07119
R
ISNS
C
IFLT
6
GND
UDG-07120
Figure 22. Oscillator Components
Figure 23. Current Sense Components
14
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