
MP4031—PRIMARY-SIDE–CONTROLLED, OFFLINE LED CONTROLLER WITH PFC
MP4031 Rev.1.03 www.MonolithicPower.com 6
9/5/2014 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2014 MPS. All Rights Reserved.
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
also detect over-voltage and over-current conditions. Over-voltage occurs if V
ZCD
exceeds
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.