MP2632 datasheet(29/37 Pages) MPS

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MP2632

– ALL-IN-ONE, 3A SW CHARGER, 3A BOOST

MP2632 Rev.1.0

www.MonolithicPower.com

6/24/2016

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

Table 3: Indication at Charge Mode

Operation Status

LED1 to LED4 State

Normal charging

Depending on the battery

voltage, LEDx blinks at

1Hz, (refer to Fuel Gauge

Indication section)

Charge full

LED1 to LED4 are all

turned on

VIN UVLO

LED1 to LED4 are all

turned off

VIN OVP, NTC fault,

battery OVP

LED1 to LED4 are all

blinking at 1Hz

Slope Compensation

HS Sense Current

HS Signal

Comp

600kHz

Constant Off Time

Lower the Fsw to support larger Duty

Figure 13: Constant-Off Time Operation Profile

Boost Mode Operation

Low-Voltage Start-Up

The minimum battery voltage required to start up

the circuit in boost mode is 2.9V. Initially, when

VSYS is less than VBATT, the IC works in down

mode. In this mode, the synchronous P-FET

stops switching and its gate connects to VBATT

statically. The P-FET stays off for as long as the

voltage across the parasitic CDS (VSW) is lower

than

VBATT. When the voltage across CDS

exceeds VBATT, the synchronous P-FET enters

linear mode, allowing the inductor current to

decrease and flow into SYS. Once VSYS exceeds

VBATT, the P-FET gate is released, and normal

closed-loop PWM operation is initiated. In boost

mode, the battery voltage can drop as low as

2.5V without affecting circuit operation.

SYS Disconnect and Inrush Limiting

The IC can achieve true output disconnect by

eliminating body diode conduction of the internal

P-FET rectifier. VSYS can go to 0V during

shutdown, drawing no current from the input

source. It also allows for inrush current limiting at

start-up, minimizing surge currents from the input

supply. To optimize the benefits of the output

disconnect,

avoid

connecting

external

Schottky diode between SW and SYS.

Board layout is extremely critical for minimizing

voltage overshoot at SW due to stray inductance.

Keep the output filter capacitor as close to SYS

as possible, and use very low ESR/ESL ceramic

capacitors tied to a good ground plane.

Boost Output Voltage Setting

In boost mode, the IC programs the output

voltage

internally

according

the

load

connected to SYS (5.1V or 5.2V) and provides

built-in output over-voltage protection (OVP) to

protect the device and other components against

damage when VSYS goes beyond 6V. Once

output over-voltage occurs, the IC turns off the

boost converter. When the voltage on VSYS drops

to a normal level, the boost converter restarts

again when PB is set from high to low for more

than 1.5ms.

Boost Output Current Limiting

The IC integrates a programmable output current

limit function in boost mode. If the boost output

current exceeds this programmable limit, the

output current is limited at this level and the SYS

voltage begins to drop down. OLIM programs the

current limit threshold up to 3.0A, per Equation

(5):

OLIM

1500

(A)

(k ) RS1(m )



 



(5)

MP2632 Datasheet(PDF) 29 Page - Monolithic Power Systems

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