TK75020 Datasheet, PDF (1/11 Pages) TOKO, Inc – ZVS RESONANT CONTROLLER

TK75020
ZVS RESONANT CONTROLLER
FEATURES
s Optimized for Off-Line and Battery Powered
Operation
s Internal Zero-Voltage Detector
s Soft-Start
s Pulse-by-Pulse Current Limit
s Overdissipation Protection with Soft-Start
s Overvoltage Protection with Soft-Start
s Low-Current Standby mode
s Programmable On/Off Timing
s Enable Control
APPLICATIONS
s Cold Cathode Fluorescent Lamps
s Resonant Power Supplies
s Power Supplies for Notebook Computers
s Power Supplies for Personal Electronics
DESCRIPTION
The TK75020 is a low-cost, high-performance Zero-Voltage
Switching (ZVS) controller IC. The primary applications
are in inverters for Cold Cathode Fluorescent Lamps
(CCFL) and in ZVS quasi-resonant or multi-resonant
converters. The combination of a unique (patent-pending)
control concept and a ZVS resonant inverter generates
low-distortion sine wave for the fluorescent lamp, leading
to extended lamp life and high luminous efficiency. The IC
features all necessary circuits of a controller for such
applications, including externally adjustable timing
parameters (frequency, T_on(min), T_off(max)), current limit,
Soft-Start, enable, error amplifier, and a trimmed reference.
The same reference is used for undervoltage protection
and other critical internal biases. Supply current in the “off”
mode is kept at a minimum level (2 µA typical). Special
care has been taken to avoid undesirable turn-on of the
external power MOSFET when sufficient supply voltage is
not available, or when the device is held in the off mode.
Even with no V_cc applied, the drive pin of the IC will sink in
excess of 20 mA while maintaining the voltage below 1 V
to prevent that leakage currents turn on the power MOSFET.
An internal zero-voltage detector monitors the voltage
across the MOSFET and ensures that the turn-on will only
take place under zero-voltage conditions. A unique
overdissipation protection prevents the overheating of the
power MOSFET in case the zero-voltage switching is lost.
The TK75020 is available in a 14-lead surface mount
package.
TK75020
ORDERING INFORMATION
TK75020
Tape/Reel Code
TAPE/REEL CODE
TL: Tape Left
75020
DRV
GND
OVP
EN
CT
TOFF(MAX)
TON/SS
VCC
Vref
CL
ZVD
EAOUT
EAINV
ODP
January 1999 TOKO, Inc.
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