# High Power Dimming LED Driver with PT4115

I was searching for a LED driver that can also act as dimmer for my 10 watts LEDs and found the PT4115 IC which is kind of interesting. It operates from an input supply between 6V and 30V and provides an externally adjustable output current of up to 1.2A, and theoretically can provide up to 30W output power.

The dimming effect is achieved using variable DC voltage by adjusting a variable resistor or PWM signal, for example from a 555 IC. A logic level below 0.3V at DIM forces PT4115 to turn off the LED and the logic level at DIM must be at least 2.5V to turn on the full LED current. The frequency of PWM dimming ranges from 100Hz to more than 20 kHz.

Dimming with the ‘DIM’ pin on the PT4115

The dimming effect is achieved using PWM provided by an Arduino UNO board.

The DIM pin can be driven by an external DC voltage between 0.5V and 2.5V. If the voltage is higher than 2.5V the output current will be constant and won’t increase.

## Schematic of the LED Driver with Dimmer Circuit

The circuit is quite simple and uses a 12VAC to 24VAC power supply or you can provide DC voltage that must not exceed 30V but your must remove D1, D2, D3 and D4 diodes. The Rs resistor is calculated using this formula: Rs = 0.1 / Iout (A). For example if we need a 500mA output current to drive the LED then Rs = 0.1 / 0.5A = 0.2Ω (200mΩ)

The value of coil L can be choosed using the table below:

Components value

• D1 … D4 = rectifier diodes
• Cin = 100µF/35V
• D5 = 1N5819
• Rs and L = read the article
##### Related Tutorials

Is the PT4115 IC capable to drive a 10W LED chip (3×3 LEDs) with a 900mA output current from a 12V input supply?

• Robin Cavell
• Nikhil

Please give the market price of pt4115 IC. Is it available in INDIA?

• Nikhil

Please give the market price of pt5115 IC. Is it available in INDIA?

• Pulak

what should be the current and voltage specification of 5watt led module!

• Daryl Jones

“DC voltage that must not exceed 30V but your must remove D1, D2, D3 and D4 diodes”

Leaving the diodes (bridge) in the circuit for DC use will provide protection against a reverse polarity connection or inadvertent connection of an AC supply.

• Vijay Chakrawar

First time I seen efficient driver circuit , please share the material source from Mumbai like name s or websites of shops.
Its very useful article as the market cost of efficient driver is Rs.100 to 150 for 3 Watt. ( series combination of 1 watt lED’s).

• Vijay Chakrawar

First time I seen efficient driver circuit , please share the material source from Mumbai like name s or websites of shops.
Its very useful article as the cost of efficient driver is Rs.100 to 150 for 3 Watt. ( series combination of 1 watt lED’s).

• T.K.Hareendran

Interesting design! Let me know at least one online source, from where I can buy one piece for my next-level experiment.Thanks in advance!

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