Datasheet

0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09
0.1
0.11
0.12
0.13
0.14
0.15
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
V -OutputVoltage-V
O
PrechargeCurrent- A
VBAT=1.2V
VBAT=1.8V
VBAT=2.4V
VBAT=3.6V
VBAT=5V
Power-Save Mode
TPS61070 , TPS61071
TPS61072 , TPS61073
www.ti.com .......................................................................................................................................................... SLVS510C – JULY 2006 – REVISED MARCH 2009
Figure 22. Precharge and Short-Circuit Current
After charging the output capacitor to the input voltage, the device starts switching. If the input voltage is below
1.8 V, the device works with a fixed duty cycle of 70% until the output voltage reaches 1.8 V. After that the duty
cycle is set depending on the input output voltage ratio. Until the output voltage reaches its nominal value, the
boost switch current limit is set to 50% of its nominal value to avoid high peak currents at the battery during
start-up. As soon as the output voltage is reached, the regulator takes control, and the switch current limit is set
back to 100%.
The TPS61070 and TPS61073 are capable of operating in two different modes. At light loads, when the inductor
current becomes zero, they automatically enter the power-save mode to improve efficiency. In the power-save
mode, the converters only operate when the output voltage trips below a set threshold voltage. It ramps up the
output voltage with one or several pulses and returns to the power-save mode once the output voltage exceeds
the set threshold voltage. If output power demand increases and the inductor current no longer goes below zero,
the device again enters the fixed PWM mode. In this mode, there is no difference between the PWM only
versions TPS61071 and TPS61072 and the power-save mode enabled versions TPS61070 and TPS61073.
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Product Folder Link(s): TPS61070 TPS61071 TPS61072 TPS61073