MP2263

– 30V, 3A, LOW IQ, SYNCHRONOUS, STEP-DOWN CONVERTER

MP2263 Rev. 1.0

www.MonolithicPower.com

11

6/22/2016

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

© 2016 MPS. All Rights Reserved.

OPERATION

The MP2263 is a synchronous, step-down,

switching regulator with integrated, internal, high-

side and low-side power MOSFETs. It provides

3A of highly efficient output current with current-

mode control. The MP2263 has a wide input

voltage range, programmable 350kHz to 2.5MHz

switching frequency, external soft start, and

current limit. Its very low operational quiescent

current makes it suitable for battery-powered

applications.

PWM Control

At moderate-to-high output currents, the MP2263

operates in a fixed-frequency, peak-current-

control mode to regulate the output voltage. A

PWM cycle is initiated by the internal clock. At

the rising edge of the clock, the high-side power

MOSFET (HS-FET) turns on and remains on until

its current reaches the value set by the COMP

switch is off, the low-side MOSFET (LS-FET)

turns on and remains on until the next cycle

begins. If the current in the HS-FET does not

reach the COMP-set current value in one PWM

period, the HS-FET remains on, saving a turn-off

operation.

Advanced Asynchronous Mode (AAM)

The MP2263 employs advanced asynchronous

mode (AAM) functionality to optimize efficiency

during light-load or no-load conditions. AAM is

selectable. AAM is enabled by connecting MODE

to a low level or floating MODE. AAM is disabled

by connecting MODE to a high level.

When AAM is enabled, the MP2263 first enters

non-synchronous operation for as long as the

inductor current approaches zero at light load. If

the load is further decreased or is at no load,

AAM or sleep mode, which consumes very low

quiescent current to improve light-load efficiency

further.

In AAM, the internal clock is reset whenever

taken as the benchmark for the next clock. When

CCM, which have a constant switching frequency.

AAM Mode

(MODE = Low)

Inductor

Current

t

t

t

Load

Decreased

PWM Mode

(MODE = High)

Inductor

Current

t

t

t

Load

Decreased

Figure 2: AAM and PWM Mode

The MP2263 has a mode selection function. Pull

MODE low or float MODE to set auto PFM/PWM

mode; pull MODE to VCC to set forced PWM

mode. MODE is pulled down internally. Select

MODE before the part starts up.

Error Amplifier (EA)

The error amplifier (EA) compares the FB voltage

with the internal reference (typically 0.8V) and

outputs a current proportional to the difference

between the two. This output current is then used

to charge the internal compensation network to

MOSFET current.

Bias and VCC Regulator

Most of the internal circuitries are powered by the

internal regulator. The MP2263 has two internal

regulators (see Figure 3). The regulator LDO1

takes the VIN input and operates in the full VIN

range. When VIN is greater than 5.0V, the output

of the regulator is in full regulation, and VCC is

5V. When VIN is lower than 5V, the output

degrades.

Another regulator, LDO2, is powered by BIAS.

Connect BIAS to an external power source. Keep

the BIAS voltage higher than 4.8V. VCC and the

is greater than 5V, the output of the regulator is

lower than 5V, the output degrades.

is enabled, LDO1 is disabled. For a 5V output

efficiency. The diode (D1) between BIAS and the

internal circuit

is used for current reverse

blocking. Since LDO1 has no reverse block

BIAS to GND if BIAS is not used.