MP2681 – CC/CV CONTROLLER WITH FULL PROTECTION

MP2681 Rev.1.01

www.MonolithicPower.com

9

12/25/2013

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© 2013 MPS. All Rights Reserved.

OPERATION

T1

+

Flyback

Primary

C

NTC

ID

...

Battery

Detection

Charge

On/Off

Control

Temperature

Sense

Current

Sense

Indication

Control

Core

Current

Reference

Voltage

Reference

CC/ CV

Control

Voltage

Sense

LED

To

Primary

BT+

BT-

Fixed

Pre-Charge

CR

Figure 1 — Functional Block Diagram

Charge Voltage Setting

The MP2681 can support 6 different types of

battery configurations: 3S1P, 3S2P, 4S1P, 4S2P,

5S1P and 5S2P using a dedicated ID resistor pin.

When a battery pack configuration is detected

through the ID resistor, the charge voltage is

automatically set internally, different battery pack

implementations require different ID resistor

values. The ID pin of the MP2681 is connected to

the ID resistor in the battery pack and pulled up

to the LDO pin by a 20kΏ resistor as shown in

Figure 2. Every battery configuration will have a

pre-set Vid value. As such, the MP2681 will

the inserted battery configuration. As the battery

changes among the six pre-set configurations the

MP2681detects

such

condition,

and

automatically modifies the resistor divider from

VDD pin as shown in Figure 3. Charge current as

well as other charge parameters will change

accordingly.

Figure 2 — Battery Pack Pin Connection

Additionally, if the battery pack does not have an

ID resistor, the charge termination voltage can be

configured by setting a dedicated voltage to the

representing

each

battery

configuration