CY8CLEDAC02 Datasheet, PDF (1/20 Pages) Cypress Semiconductor – AC-DC Controller for Dimmable LED Lighting

Features
■ AC offline input range from 80 to 277 VAC
■ Up to 25 W output power range
■ Intelligent wall dimmer detection:
❐ Leading edge (R, RL) dimmers
❐ Trailing edge (RC, RLC) dimmers
❐ No dimmer
■ Wide dimming range from 2 to 100 percent
■ Resonant control to achieve high efficiency
(85 percent without dimmer)
■ Meets harmonic requirement with high power factor
(0.7 without dimmer)
■ Primary-side sensing eliminates opto-isolators
■ Tight LED current regulation (typically < + 2.5 percent)
■ Low startup current (typically 10A)
■ Low startup time (typically 0.5 s with active startup)
■ Multiple protection features:
❐ Output overvoltage protection (OOVP)
❐ Output short circuit protection (OSCP)
❐ Overtemperature protection (OTP)
❐ Current-sense resistor short protection (CSSP)
❐ Peak current limit protection (PCLP)
❐ Single-point fault protection
■ Applications:
❐ Dimmable offline LED driver
❐ Dimmable LED replacement lamps
❐ Dimmable LED luminaires
CY8CLEDAC02
AC-DC Controller for Dimmable
LED Lighting
Description
The CY8CLEDAC02 is a high performance offline LED driver,
designed to interface directly with most conventional phase cut
based wall dimmers. The device uses proprietary digital control
technology to provide automatic detection of dimmer type
(leading or trailing edge). It automatically generates dimming
signals for LED loads and has the ability to dim down to 2
percent. It modulates LED brightness using a linear dimming
scheme and switches to a pulse width modulation (PWM) based
dimming scheme for output current levels lower than 20 percent
of the full load current. In PWM mode optimized dimming
frequencies in the range of 900 Hz result in zero visible flicker.
At the heart of a CY8CLEDAC02 based system is the chopping
circuit which provides the load necessary to enable correct wall
dimmer operation. It also improves PF when there is no dimmer
on the line.
The devices’ proprietary primary side sensing enables tight LED
current regulation and eliminates the need for secondary
feedback circuitry. No opto-couplers are necessary to meet UL
isolation requirements; enabling flyback conversion with
automatic isolation.
The CY8CLEDAC02 operates in quasi-resonant mode to
achieve high efficiency. This mode of operation helps minimize
external component count and simplifies EMI design, lowering
the total bill of material cost.
The device’s cycle-by-cycle adaptive digital regulation uses
critical discontinuous conduction mode (CDCM) when driving
LED loads. The control algorithm for cycle-by-cycle regulation
has internal compensation for guaranteed system phase and
gain margins; requiring no external components for loop
compensation.
The CY8CLEDAC02 has full featured circuit protection not
normally available with other primary-side control solutions. The
built-in protection includes output overvoltage protection, output
short circuit protection, overtemperature protection,
current-sense resistor short protection, and peak current limit
protection. It also enables automatic LED brightness adjustment
to compensate for temperature drift by simply connecting a NTC
resistor to the V_T pin.
Cypress Semiconductor Corporation • 198 Champion Court
Document Number: 001-54879 Rev. *C
• San Jose, CA 95134-1709 • 408-943-2600
Revised October 26, 2010
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