Texas Instruments bq25570, Руководство пользователя

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R1
D1
C A
BAT+
GND
Test and Measurment Summary
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The battery (storage element) can be replaced with a simulated battery. Often electronic 4 quadrant loads
give erratic results with a “battery charger” due to the charger changing states (fast-charge to termination
and refresh) while the electronic load is changing loads to maintain the “battery” voltage. The charging and
loading get out of phase and create a large signal oscillation which is due to the 4 quadrant meter. A
simple circuit can be used to simulate a battery and works well and can quickly be adjusted for voltage. It
consists of load resistor (~10
Ω , 2 W) to pull the output down to some minimum storage voltage (sinking
current part of battery) and a lab supply connected to the BAT pin via a diode. The lab supply biases up
the battery voltage to the desired level. It may be necessary to add more capacitance across R1.
3.1 Test Setups and Results
3.1.1 Boost Charger Efficiency
The test setup is shown in Figure 2 . The specific equipment used for the test results in Figure 3 and
Figure 4 is listed below:
1. VIN_DC was connected to a Keithley 2420 source-meter configured as a current source with voltage
compliance (clamp) set to the open circuit voltage.
2. VSTOR was connected a Keithley 2420 source-meter configured as a voltage source set to the
VSTOR voltage. The current sunk by the source-meter was the output current of the charger
8 User's Guide for bq25570 Battery Charger Evaluation Module for Energy SLUUAA7A – July 2013 – Revised August 2014
Harvesting
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