MP44019

– CRM/DCM MULTI-MODE PFC CONTROLLER WITH SECOND OVP

MP44019 Rev. 1.0

MonolithicPower.com

15

4/30/2021

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© 2021 MPS. All Rights Reserved.

OPERATION

The MP44019 is designed to provide simple,

high-performance active power factor correction

(PFC) using minimal external components.

CrM/DCM multi-mode allows the MP44019 to

operate in transitional modes under heavy loads.

Multi-mode

allows

the

device

to

convert

seamlessly into discontinuous conduction mode

(DCM) under light loads, which maximizes

operating efficiency.

The MP44019 features a very low supply

current, which meets typical standby power

requirements. The no-load power loss is usually

below 50mW.

Start-Up and Brown-In

Figure 2 shows the typical start-up timing

diagram.

As VCC gradually builds up and reaches VCC_ON

(typically 10.7V) at t1, the IC is enabled. Then

the IC starts to sense the brown-in condition

through MAINSIN. When the sampled peak

voltage exceeds VMAINS_BI (typically 1V), the

device starts to switch at t2. The MP44019

implements a COMP soft start-up, and the bus

voltage achieves its regulation voltage at t3.

t

COMP

VREC

t

t

BIBO

VCC

PFC_VCCON =

10.7V

PFC_VCCOFF =

8.7V

UVLO

FAULT

PFC_GATE

BO Timer out =

50ms

t

t

t

t

PFC VOUT

t1

t2

t3

t4

t5

0.8

Figure 2: Start-Up and Brown-In/Brownout

Brownout Function

The AC peak voltage is continuously sensed by

MAINSIN. Because the AC peak voltage falls

below VMAINS_BO (typically 0.9V) at t4, the device

continues switching until the brownout timer

(typically 50ms) ends at t5. Then the IC confirms

the brownout condition.

At this point, the PFC stops switching and COMP

is pulled down to 0V. The device restarts with a

COMP soft start if the peak MAINSIN voltage

exceeds VMAINS_BI (typically 1V).

Enhanced Dynamic Response

The boost PFC output voltage is sensed on FB,

and is compared with the internal reference (VREF,

typically 2.5V) (see Figure 13 on page 19). RO1

is recommended to be 10M

Ω to minimize power

consumption.

RO2

can

be

calculated

with

Equation (1):







O1

R

O2

OUT

R

RV

R

VV

(1)

The voltage compensation tank is connected

from COMP to GND. Proportional integral (PI)

control with a high-frequency pole is typically

used for compensation.

Figure 3 shows a nonlinear GM, which achieves

both excellent loop regulation in steady state and

enhanced

dynamic

response

during

load

transient. If the output voltage is detected with an

undershoot of 4%, the gain increases to four

times the normal gain. A higher gain can pull up

COMP quickly and reduce the voltage drop

during the load step.

70µA

10µA

-10µA

-50µA

FB

ICOMP

2.4

2.6

2.2

100µs

2.5

2.65

300µs

0.8ms

Figure 3: Nonlinear GM

If the output voltage is above or below the normal

voltage with an overshoot of 4%, the gain

increases to eight times the normal gain. This

ensures that COMP is quickly pulled down to

avoid triggering over-voltage protection (OVP).