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© 2021 ROHM Co., Ltd.
No. 64UG016E Rev.001
MAY.2021
User’s Guide
Battery Charger Series
Linear Charger for Low Voltage Battery
BD71631QWZ EVK
BD71631QWZ-EVK-001 (5V→4.2V, 0.1A)
Introduction
This user’s guide provides the necessary steps to operate the EVK of ROHM’s BD71631QWZ linear charger for low charge
voltage battery. This include the external parts, operating procedures, and application data.
Description
This EVK is for evaluating the linear charging IC BD71631QWZ, and charges 4.2V from the 5V input voltage. BD71631QWZ
accepts a power supply input range of 2.9V to 5.5V and generates a charging battery voltage ranging from 2.0V to 4.7V using
external resistors. If the charging current is VIN ≥ 4 V, it can be used up to 300 mA under the condition of VIN-VOUT ≥ 1 V and
up to 100 mA under the condition of VIN-VOUT ≥ 0.3 V. If 2.9 V ≤ VIN ≤ 5.5 V, it can be used up to 30 mA under the condition of
VIN-VOUT ≥ 0.3 V. The charging current can be set with an external resistor. The termination current can be set from 50 μA to 10
mA using external resistors. Additional protection functions include a built-in Fixed 10-hour Safety Timer, UVLO (Under Voltage
Lock Out), TSD (Thermal Shutdown Detection), and Battery Over Voltage Protection.
Application
Low Voltage Battery Products
Li-ion 1Cell Battery Products
Operating Limits
Table 1. Operating Limits
Parameter
Symbol
Min
Typ
Max
Units
Conditions
Input Voltage
VIN
4.5
5.0
5.5
V
Charge Voltage
VCHG
4.2
V
RVFB1=180kΩ, RVFB2=30kΩ
Pre Charge Voltage
VPRE
0.7
V
Re Charge Voltage
VRECHG
3.0
V
RVFBRE1=120kΩ, RVFBRE2=30kΩ
Charge Current
ICHG
98
mA
RICHG1=5.1kΩ
Termination Current
ITERM
0.98
mA
RITERM=51kΩ
VOUT Leak Current
IBAT
0
1
µA
VIN=Open
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© 2021 ROHM Co., Ltd.
No. 64UG016E Rev.001
MAY.2021
User’s Guide
BD71631QWZ-EVK-001
EVK
Figure 1. BD71631QWZ-EVK-001(Top View)
EVK Schematic
120k
180k
30k 30k
5.1k
51k
U1
Figure 2. BD71631QWZ-EVK-001 Circuit Diagram
Operating Procedure
1. Turn off the DC power supply and connect the GND terminal of the power supply to the GND1 terminal of the EVK.
2. Connect the positive terminal of the DC power supply to the VIN pin of the EVK.
3. Connect the positive terminal of the DC power supply that can sink to the VOUT pin of the EVK.
4. Connect a current meter between the VOUT terminal of the EVK and the positive terminal of DC power supply of VOUT.
5. Connect a voltmeter between the VOUT terminal and GND terminal of EVK.
6. Turn on the DC power supply of VOUT.
7. Turn on the DC power supply of VIN. The power supply on the VOUT side is set to 4.2V or lower, charging will start and
current will flow through the ammeter.
(Caution) This EVK does not support hot plug. Do not perform hot plug test.