MP2626 datasheet(29/34 Pages) MPS

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MP2626 – SINGLE CELL LI-ION SWITCHING CHARGER WITH USB OTG

MP2626 Rev. 1.0

www.MonolithicPower.com

2/28/2015

MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.

APPLICATION INFORMATION

COMPONENT SELECTION

Setting the Charge Current in Charge Mode

In charge mode, both the external sense resistor,

RS1, and the resistor RISET connect to the ISET

pin to set the charge current (ICHG) of the MP2626.

(see the Typical Application Circuit)

Given ICHG and RS1, RISET can be calculated as:

)

((

)

(

2800

)

(

CHG

ISET

(8)

For example, for ICHG=2A, and RS1=50mΩ, thus:

RISET=28kΩ.

Setting the input Current Limiting in Charge

Mode

In charge mode, connect a resistor from the ILIM

pin to AGND to program the input current limit.

The relationship between the input current limit

and setting resistor is as following:

ILIM

IN _ LIM

40.5(k ) 1(A)

R(k )

I(A)

Ω×

Ω=

(9)

Where, RILIM must exceed 15kΩ so that IIN_LIM is

in the range of 0A to 2.7A.

For

most

applications,

use

RILIM=45kΩ

(IUSB_LIM=900mA) for USB3.0 mode, and use

RILIM=81kΩ (IUSB_LIM=500mA) for USB2.0 mode.

Setting the Input Voltage Range for Different

Operation Modes

A resistive voltage divider from the input to PWIN

pin determines the operation mode of MP2626.

PWIN

R4 R3

=×

(10)

When MP2626 works in the charge mode (see

Table1), the voltage on PWIN should be between

0.8V and 1.15V. For a wide operating range, use

a maximum input voltage of 6V as the upper

threshold for a voltage ratio of:

PWIN

V1.15

R4 R3

(11)

With the given R4 and R3,

PWIN

−

=×

(12)

For a typical application, start with R4=5.1kΩ, R3

is 21.5kΩ.

Setting the Input Voltage Regulation in

Charge Mode

In Charge mode, connect a resistor divider from

the VIN to GND with tapped to REG pin to

program the input voltage regulation.

IN_ R

REG

R6 R5

(V)

=×

(13)

With the given R6, R5 is:

IN _ R

REG

R6(V)

−

=×

(14)

For a preset input voltage regulation value, say

4.75V, start with R6=5.1kΩ, R5 is 15kΩ.

NTC Function in Charge Mode

Figure 13 shows that an internal resistor divider

sets the low temperature threshold (VTL) and high

temperature threshold (VTH) at 66.3%·VPMID and

35%·VPMID respectively. For a given NTC

thermistor, select an appropriate RT1 and RT2 to

set the NTC window.

Cold

NTC

Cold

NTC

SYS

(15)

T 2

NTC _ Hot

SYS

T 2

NTC _ Hot

R// R

TH 35%

R // R

(16)

Where RNTC_Hot is the value of the NTC resistor at

the upper bound of its operating temperature

range, and RNTC_Cold is its lower bound.

The two resistors, RT1 and RT2, independently

determine the upper and lower temperature limits.

This flexibility allows the MP2626 to operate with

most NTC resistors for different temperature

range requirements. Calculate RT1 and RT2 as

follows:

NTC _ hot

NTC _ Cold

NTC _ Hot

(TL TH)

TH TL (R

)

××

−

××

−

(17)

MP2626 Datasheet(PDF) 29 Page - Monolithic Power Systems

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