Datasheet

Vphase
Vin
Vstor
Vbat
Test Summary www.ti.com
3.3.6 Operation Near OV With 100-Ω Battery Impedance
1. Connect scope probes CHI→CH4: V
PH(TP16)
, V
STOR
, V
IN
, V
BAT
; set V
P/S#1
to 1.3 VDC and V
BAT
to 3.00
VDC. Connect the power sources with their respective source impedance to the EVM. V
IN
source
impedance should be 20Ω and the battery impedance should be 100Ω. Set VSTOR and VBAT to
20mVDC/div and 3.135VDC offset (3.135VDC was the average VBAT [OV] measurement), 1 ms/div.
Turn on sources.
2. The input source has enough energy to charge the V
STOR
up to the OV setting; and. when the boost
converter stops switching V
STOR
will discharge down to the battery’s cell voltage which is ~3V which is
below the OV reset hysteresis. See Figure 7 for operation near OV. Note the hysteresis of V
STOR
is
around 35mV here, but this can vary depending on the input, output voltage, the source and battery
impedance, and the number of pulses for each operation period of the boost converter.
Figure 7. EVM Operation Near OV With 100-Ω Battery Impedance
10
bq25504 EVM – Ultra Low Power Boost Converter with Battery Management for SLUU654A–October 2011–Revised October 2011
Energy Harvester Applications
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