MP4031—PRIMARY-SIDE–CONTROLLED, OFFLINE LED CONTROLLER WITH PFC

MP4031 Rev.1.03

www.MonolithicPower.com

6

5/8/2013

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PIN FUNCTIONS

Pin #

Name

Pin Function

1

MULT

Internal Multiplier Input. Connect to the tap of resistor divider from the rectified voltage of

the AC line. The half-wave sinusoid signal to this pin provides a reference signal for the

internal current control loop. The MULT pin also detects the TRIAC dimming phase.

2

ZCD

Zero-Current Detection. A negative going edge triggers the internal MOSFET’s turn-on

signal. Connect to the tap of a resistor divider from the auxiliary winding to GND. ZCD can

the over-voltage-protection (OVP) threshold after a 2µs blanking time when the internal

MOSFET turns off.

3

VCC

Supply Voltage. Supplies power for both the control signal and the internal MOSFET’s gate

driver. Connect to an external bulk capacitor—typically 22µF with a 100pF ceramic

capacitor to reduce noise.

4

CS/DIM

Current Sense and Analog dimming. An internal comparator compares the Current Sense

voltage to the internal sinusoidal current reference to determine when the MOSFET turns

off. If the voltage exceeds the current-limit threshold of 2.3V after the leading edge blanking

time and during the turn-on interval, the gate signal turns off. In Triac dimming, this pin is

connected directly to S Pin for current sense, and in Analog dimming, the Analog dimming

signal is added through this pin as the typical application shows.

5

S

Internal Low-Side Main MOSFET Source. Connect a resistor from this pin to GND to sense

the internal MOSFET current.

6

D

Internal Low-Side Main MOSFET Drain. This pin internally connects to VCC via a diode and

a JFET to form an internal charging circuit for VCC. Connect to the source of the high-side

MOSFET.

7

GND

Ground. Current return of the control signal and the gate drive signal.

8

COMP

Loop Compensation. Connects to a compensation network to stabilize the LED driver and

accurately control the LED driver current. The COMP pin can also monitor for overload

conditions: if the COMP voltage rises above 5V, the overload protection triggers.