Document
STR-W6753
Quasi-Resonant Topology Primary Switching Regulators
Features and Benefits
▪ Quasi-resonant topology IC Low EMI noise and soft switching
▪ Bottom-skip mode Improved system efficiency over the entire output load by avoiding increase of switching frequency
▪ Auto-Standby mode Lowers input power at very light output load condition
▪ Avalanche-guaranteed MOSFET Improves system-level reliability and does not require VDSS derating
▪ 650 V / 1.70 Ω ▪ Various protections Improved system-level reliability Continued on the next page…
Package: 6-pin TO-220
Not to scale
Description
The STR-W6753 is a quasi-resonant topology IC designed for SMPS applications. It shows lower EMI noise characteristics than conventional PWM solutions, especially at greater than 2 MHz. It also provides a soft-switching mode to turn on the internal MOSFET at close to zero voltage (VDS bottom point) by use of the resonant characteristic of primary inductance and a resonant capacitor.
The package is a fully molded TO-220, which contains the controller chip (MIC) and MOSFET, enabling output power up to 58 W with universal input or 120 W with a 230 VAC input. The bottom-skip mode skips the first bottom of VDS and turns on the MOSFET at the second bottom point, to minimize an increase of operating frequency at light output load, improving system-level efficiency over the entire load range.
There are two standby modes available to reduce the input power under very light load conditions. The first is Auto-Standby mode, which is internally triggered by periodic sensing, and the other is a manual standby mode, which is executed by clamping the secondary output. In general applications, the manual standby mode reduces the input power further compared to Auto-Standby mode.
The soft-start mode minimizes surge voltage and reduces power stress to the MOSFET and to the secondary rectifying
Continued on the next page…
Typical Application Diagram
P S1
+B
ErrAmp A
D
1
4
STR-W6753
VCC
Controller (MIC)
6
FB
37 S/GND OCP/BD
5 SS /OLP
ROCP
RX CX
D S2
B SI
GND Standby ON/OFF
LowB
Standby Out
GND
A For ErrAmp, Sanken SE series device recommended B For SI, Sanken linear regulator IC recommended
28103.31
SANKEN ELECTRIC CO., LTD.
http://www.sanken-ele.co.jp/en/
STR-W6753
Quasi-Resonant Topology Primary Switching Regulators
Features and Benefits (continued)
▫ Pulse-by-pulse drain overcurrent limiting ▫ Overvoltage protection (bias winding voltage sensing),
with latch ▫ Overload protection with latch ▫ Maximum on-time limit
Selection Guide
Part Number STR-W6753
Package TO-220
Description (continued)
diodes during the start-up sequence. Various protections such as overvoltage, overload, overcurrent, maximum on-time protections and avalanche-energy-guaranteed MOSFET secure good systemlevel reliability.
Applications include the following: ▪ Set Top Box ▪ LCD PC monitor, LCD TV ▪ Printer, Scanner ▪ SMPS power supplies
Absolute Maximum Ratings at TA = 25°C
Parameter
Symbol
Conditions
Drain Current1 Maximum Switching Current2 Single Pulse Avalanche Energy3 Input Voltage for Controller (MIC) SS/OLP Terminal Voltage FB Terminal Inflow Current FB Terminal Voltage OCP/BD Terminal Voltage
MOSFET Power Dissipation4
IDpeak IDmax EAS VCC VSSOLP IFB VFB VOCPBD
PD1
Single pulse TA = –20°C to 125°C Single pulse, VDD = 99 V, L = 20 mH, ILpeak = 3.6 A
IFB within the limits of IFB With infinite heatsink Without heatsink
Controller (MIC) Power Dissipation Operating Internal Leadframe Temperature Operating Ambient Temperature Storage Temperature Channel Temperature 1Refer to figure 2
PD2 VCC × ICC TF Recommended operation temperature, see cautions TOP Tstg Tch
2IDMAX is the drain current determined by the drive voltage of the IC and the threshold voltage, Vth, of the MOSFET 3Refer to figure 3
4Refer to figure 5
Rating 11.2 11.2 145 35
–0.5 to 6.0 10
–0.5 to 9.0 –1.5 to 5.0
26.0 1.3 0.8 –20 to 115 –20 to 115 –40 to 125 150
Unit A A mJ V V mA V V W W W °C °C °C °C
All performance characteristics given are typical values for circuit or system baseline design only and are at the nominal operating voltage and an ambient temperature, TA, of 25°C, unless otherwise stated.
28103.31
SANKEN ELECTRIC CO., LTD.
2
STR-W6753
Quasi-Resonant Topology Primary Switching Regulators
4
VCC
+ -
OVP
Start Stop Burst
RQ S
+ -
OLP
Reg and Iconst
Burst Control
Protection Latch
R Q
S
Drive Reg Delay
Control IC
OSC Max On
S
Q R
BSD +
Soft Start
Bottom Select Counter
+ FB- -
+
OCP
BD + -
D1
3
S/GND
FB 6
OCP/BD 7
SS/OLP
5
Terminal List Table
Number 1
Name D
2 NC
3 S/GND
4 VCC
5 SS/OLP
6 FB
7 OCP/BD
Description Drain Clipped Source/ground terminal Power supply terminal Soft Start/Overload Protection terminal
Feedback terminal
Overcurrent Protection/Bottom Detection
Functions MOSFET drain No connection MOSFET source and ground Input of power supply for control circuit Input to set delay for Overload protection and Soft Start opera.