Datasheet

R3 + R2
ǒ
V
REF
* V
OUT
V
REF
* 1
Ǔ
2.7 V To 5.5 V
COMPGND
VIN
EN
IN
VREF
FB
OUT
PS_GND
SW
PowerPAD
VOUT, –12V
C2
C3
10pF
D1
TPS63700
SL03
L1
10 Hm
C6
4.7nF
10 W
C1
0.1 Fm
C4
10 Fm
C5
4x4.7 Fm
0.22 Fm
R2
121kW
R3
1.2MW
R4
100kW
VIN
COMPGND
VIN
EN
IN
VREF
FB
OUT
PS_GND
SW
PowerPAD
VOUT, –5V
C2
C3
10pF
D1
L1
4.7 Hm
C6
4.7nF
TPS63700
SL02
10 W
C1
0.1 Fm
C4
10 Fm
C5
4x4.7 Fm
0.22 Fm
R2
150kW
R3
619kW
R4
100kW
2.7VTo5.5V
VIN
TPS63700
www.ti.com SLVS530C –SEPTEMBER 2005–REVISED JUNE 2013
APPLICATION INFORMATION
Design Procedure
The TPS63700 dc-dc converter is intended for systems typically powered by a single-cell Li-ion or Li-polymer
battery with a terminal voltage between 2.7 V up to 4.2 V. Due to the recommended input voltage going up to 5.5
V, the device is also suitable for 3-cell alkaline, NiCd, or NiMH batteries, as well as regulated supply voltages of
3.3 V or 5 V.
Figure 15. Circuit for –5 Volt Output
Figure 16. Circuit for –12 Volt Output
Programming the Output Voltage
Converter
The output voltage of the TPS63700 converter can be adjusted with an external resistor divider connected to the
FB pin. The reference point of the feedback divider is the reference voltage VREF with 1.213 V. The typical value
of the voltage at the FB pin is 0 V. The minimum recommended output voltage at the converter is –15 V. The
feedback divider current should be 10 μA. The voltage across R2 is 1.213 V. Based on those values, the
recommended value for R2 should be 120 kΩ to 200 kΩ in order to set the divider current at the required value.
The value of the resistor R3 can then be calculated using Equation 1, depending on the needed output voltage
(V
OUT
):
(1)
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