MP4088 – NON

MP4088 Rev. 1.0

11/23/2015

MPS Proprietary Information

OPERATION

The MP4088 is a highly integr

effective, TRIAC dimmable LED

MP4088 requires only a minimal

external components, making it a

IC in high-line (230VAC) input and

applications, especially for small

applications. Hybrid operation mod

both good dimming performance a

output current. The power factor exc

most

applications

to

eliminate

pollution on the AC line. The integ

voltage regulator enables fast star

any perceptible delay. The powe

function at high temperatures prot

from thermal damage.

Hybrid Operation Mode

To achieve smooth TRIAC dim

MP4088

implements

proprieta

operation mode, in which the IC self

internal switching mode between

DCM during different times of the AC

hybrid operation mode actively m

latching current and holding cur

leading edge TRIAC to enable a g

factor.

The hybrid operation mode also

small dimming duty condition. The

CCM during the entire dimming on

the dimmer is set to a small dimm

higher and smoother input current c

excellent dimming performance.

Power Supply

The IC is self-supplied by the in

voltage regulator, which is drawn fro

IC begins switching, and the int

voltage regulator turns off once the

voltage regulator turns on again to

external VCC capacitor. VCC is r

In TRIAC dimming applications,

high-voltage regulator only works

dimmer is on. To maintain a suffic

capacity, a capacitor of 10μF o

recommended for VCC. If a s

capacitor cannot provide enough po

for the chip, an external chargin

recommended (see Figure 2).

N-ISOLATED, TRIAC DIMMABLE PFC LED DR

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© 2015 MPS. All Rights Reserved.

rated, cost-

driver. The

number of

competitive

non-isolated

form-factor

de achieves

nd accurate

ceeds 0.7 in

e

harmonic

grated high-

rt-up without

er de-rating

tects the IC

mming, the

ary

hybrid

f-adjusts the

CCM and

C cycle. The

aintains the

rent of the

good power

achieves a

IC works in

n time when

ming duty. A

can achieve

ternal high-

om HV. The

ternal high-

e voltage on

voltage on

ternal high-

o charge the

regulated at

the internal

s when the

cient driving

or larger is

single VCC

ower supply

ng circuit is

When VCC drops below VC

working, and the internal h

recharges the VCC capacito

Figure 2: VCC Char

When a fault conditions occ

OTP, the MP4088 stops

internal

current

sour

discharges the VCC capaci

below

the

in

regulator recharges the V

restart time can be calculate

Figure 3 shows the typical

under-voltage lockout.

Figure 3: VCC Under-Volta

Constant Current Operatio

The MP4088 is a highly in

internal feedback logic resp

sample and hold circuit t

output-current regulation.

internal sampling capacitor

voltage, indicating an insuff

the integrated MOSFET is

period is determined by th

After the on period elap

MOSFET turns off (see Figu

−

=

×+

NOR

PRO

RESTART

VCC

CC_LATCH

VCC

VCC

tC

C

I

RIVER FOR 230VAC

13

ohibited.

igh-voltage regulator

or.

rging Circuit

curs, such as OVP or

s working, and an

ce

(ICC_LATCH)

tor. After VCC drops

ternal

high-voltage

VCC capacitor. The

ed with Equation (1):

(1)

waveform with VCC

age Lockout (UVLO)

on

ntegrated driver. The

ponds to the internal

to achieve constant

The voltage of the

. When the sampling

below the reference

ficient output current,

s turned on. The on

e peak current limit.

ses, the integrated

ure 4).

−

×

OFF

PRO

VCC

REGULATOR

VCC

VCC

C

I