MP26124

–24V INPUT, 2A, 600kHz, 4S SWITCHING LI-ION BATTERY CHARGER

MP26124 Rev. 1.0

www.MonolithicPower.com

10

10/10/2017

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PIN FUNCTIONS

Pin #

Name

Description

1

VCC

IC supply voltage.

2

NTC

Thermistor input. Connect a resistor from NTC to VREF33. Connect the thermistor

from NTC to ground.

3

ACOK

4

CHGOK

Charging status indicator. CHGOK is an open-drain output. Add a pull-up resistor to

CHGOK . Logic low indicates normal charging. Logic high indicates either a completed

charge process or suspended process due to a fault.

5

VREF33

Internal linear regulator, 3.3V reference output. Bypass VREF33 to GND with a 1

μF

ceramic capacitor.

6

EN

On/off control input.

7

SGND

Definition. Connect SGND to the GND plane.

8

COMPV

V-LOOP compensation. Decouple COMPV with a capacitor and a resistor.

9

COMPI

I-LOOP compensation. Decouple COMPI with a capacitor and a resistor.

10

BATT

Positive battery terminal.

11

CSP

Battery charge current sense positive input. Connect a resistor (RS1) between CSP

and BATT. The full charge current is:

 

 

m

Ω

RS1

200mV

A

I

CHG



.

12

GND

Ground. GND is the voltage reference for the regulated output voltage. This node

should be placed outside of the switching diode (D2) to the input ground path to prevent

switching current spikes from inducing voltage noise into the part.

13

TMR

Safe timer period. A 0.1µA current charges and discharges the external capacitor

decoupled to GND. The capacitor value programs the timer period.

14

BST

Bootstrap. A charged capacitor is required to

drive the power switch’s gate above the

supply voltage. Connect a capacitor between SW and BST to form a floating supply

across the power switch driver.

15

SW

Switch output.

16

VIN

Input voltage. The MP26124 regulates an up to 24V input to a voltage suitable for

charging a 4-series Li-ion battery pack. Capacitors are required to prevent large voltage

spikes from appearing at the input.