MP2632B datasheet(34/43 Pages) MPS

34 / 43 page

MP2632B

– ALL-IN-ONE, 3A SW CHARGER, 3A BOOST

MP2632B Rev. 1.0

www.MonolithicPower.com

3/9/2018

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 on page 36)

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

600kH

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 3.2V. Initially,

when VSYS is less than VBATT, the MP2632B

works in down mode. In down mode, the

synchronous

P-channel

MOSFET

(P-FET)

stops switching, and its gate connects to VBATT

statically. The P-FET remains 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, pulse-width modulation

(PWM) operation is initiated. In boost mode, the

battery voltage can drop to as low as 2.9V

without affecting circuit operation.

SYS Disconnect and Inrush Limiting

The

MP2632B

implements

true

output

disconnect

eliminating

body

diode

conduction of the internal P-FET rectifier. VSYS

can drop to 0V during shutdown, drawing no

current from the input source. The MP2632B

also allows for inrush current limiting at start-up,

minimizing surge currents from the input supply.

optimize

the

benefits

the

output

disconnect,

avoid

connecting

external

Schottky diode between SW and SYS.

Board layout is extremely critical for minimizing

voltage

overshoot

due

stray

inductance. Keep the output filter capacitor as

close as possible to SYS and use very low

ESR/ESL ceramic capacitors tied to a good

ground plane.

Boost Output Voltage Setting

In boost mode, the MP2632B programs the

output voltage internally according to the load

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

built-in output OVP to protect the device and

other components against damage when VSYS

goes beyond 6V. Once output over-voltage

occurs, the MP2632B 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 MP2632B 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. OLIM programs the current limit

threshold up to 3.0A as shown in Equation (5):

OLIM

1500

(A)

(k ) RS1(m )



 



(5)

MP2632B Datasheet(PDF) 34 Page - Monolithic Power Systems

MP2632B Datasheet(HTML) 34 Page - Monolithic Power Systems

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43

Datasheet Download

Link URL