TPS23750
TPS23770
www.ti.com
SLVS590A–JULY 2005–REVISED AUGUST 2005
APPLICATION INFORMATION (continued)
Converter Power Stage
To
DD
+
V
1.5V
R
R
Low
Voltage
Output
LO
HI
R
C
Z
Z
−
C
FB
COMP
BYP
Error
Amplifier
Part of TPS23750
Translator
To
GATE
1.5V
+
+
Soft
start
80k
SENP
To PWM
Comparator
SEN
RSP
−
15k
20k
15k
RTN, COM, RSN
MODE
Figure 34. Buck Converter Configuration
ADDITIONAL USES OF SENP AND SEN
The level translator inputs, SENP and SEN, are not limited to the buck application shown in Figure 34. They may
be used at voltages above VDD, but within their recommended voltage range with respect to VSS. SENP draws
about 22.5 µA of current, while the SEN pin draws less than 1 µA. The SENP current can cause a small offset in
the output voltage if connected to the center tap of an output voltage divider. If necessary, the offset can be
minimized or compensated. The following example shows a method of creating a voltage greater than VDD for a
telecom application that requires a voltage greater than battery ground.
Converter Power Stage
+
R
LO
Low
C
BYP
Voltage
Output
C
OUT
R
HI
To
-
V
DD
FB
COMP
Error
Amplifier
Part of TPS23750
To
GATE
1.5V
+
+
-
SENP
SEN
RSP
Soft
start
Translator
To PWM
To current
Comparator
comparator
15k
15k
MODE
RTN, COM, RSN
Figure 35. Buck-Boost Configuration Example
21
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