IW3602-00 datasheet(8/18 Pages) DIALOG

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iW3602-00

AC/DC Digital Power Controller for

Dimmable LED Drivers

Rev. 0.8 Preliminary

iW3602-00

Datasheet

8 of 20

Pin 6 – ISENSE

Primary current sense. Used for cycle by cycle peak current

control.

Pin 7 – OUTPUT

Gate drive for the external MOSFET switch.

Pin 8 – VCC

Power supply for the controller during normal operation.

The controller starts up when VCC reaches 12V (typical) and

shuts down when the VCC voltage is below 7.5 V (typical).

High-frequencytransientsandripplescanbeeasilygenerated

on the VCC pin due to power supply switching transitions,

and line and load disturbances. Excess ripples and noises

on VCC may cause the iW3602-00 to function undesirably,

hence a decoupling capacitor should be connected between

the VCC pin and GND. A ceramic capacitor of minimum 0.1uF

connected as close as possible to the VCC pin is suggested.

9.2 Wall Dimmer Detections

Dimmer detection, or discovery, takes place during the third

cycle after start-up. The controller determines whether no

dimmer exists, or there is a leading-edge dimmer.

AC line before Wall-

dimmer

AC line after

Wall-dimmer

Figure 9.1 : Leading-Edge Wall Dimmer Waveforms

VCROSS is internally generated by comparing the digitized

VIN signal to the threshold of 0.14V. The VIN period

(tPERIOD) is measured between two consecutive rising edge

zero-crossings. tCROSS is generated by the internal digital

block (refer to Figure 9.2); when VIN_A is higher than 0.14V

tCROSS is set to high and when VIN_A falls below 0.14V tCROSS

is reset to zero. If tCROSS is much shorter than the VIN period

then a dimmer is detected. Using filtered derivatives the

9.0 Theory of Operation

The iW3602-00 is a high performance AC/DC off-line power

supply controller for dimmable LED luminaires, which uses

advanced digital control technology to detect the dimmer

type and dimmer phase to control the LED brightness. A

PWM-dimming scheme is used to modulate the LED current

with a dimming frequency of 900Hz at low dimming levels.

iW3602-00 can work with all types of leading-edge dimmers,

as well as other dimmer configurations such as R-type or

R-L type without visible flicker. The controller can also work

when no dimmer is connected.

The iW3602-00 operates in a quasi-resonant mode to

provide high efficiency and to simplify EMI design. In

addition, the iW3602-00 includes a number of key built-in

protection features. Using Dialog’s state-of-the-art primary-

feedback technology, the iW3602-00 removes the need for

secondary feedback circuitry while achieving excellent line

and load regulation. iW3602-00 also eliminates the need for

loop compensation components while maintaining stability

over all operating conditions. Pulse-by-pulse waveform

analysis allows for accurate LED current regulation. Hence,

the iW3602-00 can provide high performance dimming

solutions, with minimal external component count and low

bill of materials cost.

9.1 Pin Detail

Pin 1 – OUTPUT(TR)

Gate drive for the bleeding circuit MOSFET switch.

Pin 2 – VSENSE

Sense signal input from auxiliary winding. This pin provides

the secondary voltage feedback used for output regulation.

Pin 3 – VIN

Rectified line voltage sense input. VIN is used for dimmer

phase detection. The input line voltage is scaled down using

a resistor network. It is used for input under-voltage and

over-voltage protection. This pin also provides the supply

current to the IC during start-up.

Pin 4 – VT

External power limit and shutdown control. If the shutdown

control is not used, this pin should be connected to GND via

a resistor.

Pin 5 – GND

Ground.

IW3602-00 Datasheet(PDF) 8 Page - Dialog Semiconductor

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