POWER AND LINEAR IC SOLUTIONS

IC Cuts Rectification Parts Count by 75%

The IR1167S from International Rectifier is a smart secondary-side driver IC designed to drive N-channel power MOSFETs used as Synchronous Rectifiers (SRs) in isolated flyback converters. The device can increase overall system efficiency by 1% and reduce MOSFET temperature by 10°C, while cutting SR parts count by 75%.



Aimed at designers of high-power flyback and resonant half-bridge converters for laptops, mini-PCs, LCD and PDP TVs and switch-mode supplies for games machines, the IR1167S offers a simple, high-efficiency solution for secondary synchronous rectification. It uses a proprietary direct sensing technique to minimise wasteful secondary reactive currents and maximise efficiency.

The device can control one or more parallel N-MOSFETs to emulate the behaviour of Schottky diode rectifiers. The drain to source voltage is sensed differentially to determine the polarity of the current and turn the power switch on and off close to the zero current transition. This contrasts with traditional current sensing topologies, that require a large reversing current before they can sense the polarity changes through the MOSFETs.

The IR1167S uses a proprietary 200V HVIC technology and features a 7A gate drive. This makes it compatible with all MOSFET gate types. It is designed to permit operation in Continuous, Discontinuous and Critical Current Mode (CCM, DCM and CrCM) and both fixed and variable frequency modes at up to 500kHz.

Direct connection to IR’s wide range of 30V to 200V SR MOSFETs, featuring optimised on-resistance and gate charge characteristics, forms a total chip set solution to further maximise efficiency and power density in SR circuits.

The IC is available in either SO-8 or DIP-8 packages which are lead (Pb)-free and compliant with the Restriction of Hazardous Substances Directive (RoHS).

The company provides online design software on its myPower site (http://www.irf.com/design-center/mypower/), allowing designers to enter application conditions and performance requirements to obtain recommended IC and MOSFET chip sets which can be sorted by performance and system cost. Daughter cards are also available offering a fast and simple way to compare efficiency and simplicity of SmartRectifier solutions with diode designs and complex SR solutions.

Product Specifications

Part No.	Pack	VCC(V)	VFET(V)	Sw Freq. max (kHz)	Gate drive +/- (A)	VGATE Clamp (V)	Sleep Current max (µA)	RoHS
IR1167ASPbF	SO-8	20	<=200	500	+2/-7	10.7	200	Yes
IR1167BSbF	SO-8	20	<=200	500	+2/-7	14.5	200	Yes
IR1167APbF	DIP8	20	<=200	500	+2/-7	10.7	200	Yes
IR1167BPbF	DIP8	20	<=200	500	+2/-7	14.5	200	Yes

Features

• Secondary-side high-speed Synchronous Rectification controller
• DCM, CrCM and CCM flyback topologies
• 200V proprietary IC technology
• Fixed or variable switching frequency up to 500kHz
• Anti-bounce logic and UVLO protection
• 7A peak turn-off drive current
• Micropower start-up and ultra-low quiescent current
• 10.7V/14.5V gate drive clamp
• 50ns turn-off propagation delay
• VCC range from 11.3V to 20V
• Direct sensing of MOSFET drain voltage
• Minimal external component count
• Compatible with 1W standby, Energy Star
• Simple, powerful solution
• Direct connection and drive to all 30V-200V MOSFETs
• 8-lead SOIC and DIP-8 packages

Applications

• Laptops
• Mini-PCs
• LCD and PDP TVs
• Switch-mode supplies for games machines

For further information, including the IR1167 Datasheet and SMART Rectifier Overview, please click here.