UCC24636
- Secondary-Side SR Controller Optimized for
5-V to 24-V Output Discontinuous/Transition Mode
Only Flyback Converters - Volt-Second Balance Control Enables Highest
Rectifier Efficiency - Compatible with PSR and SSR Flyback
Controllers - Ultra Low 110-µA Standby Current Consumption
- Auto-Detect Standby Mode Disables SR Switching
for Lower No-Load
Power Consumption - SR Turn-Off Independent of RDSON and Parasitic
Inductance - Operating Frequency Up to 130 kHz
- Wide VDD Range from 3.6 V to 28 V
- Adaptive Gate Drive Clamp
- Open and Short Pin Fault Protection
The UCC24636 SR is a compact, 6-pin secondary-side synchronous rectifier MOSFET controller and driver for high efficiency Flyback converters operating in Discontinuous (DCM) and Transition mode (TM). Unlike traditional SR controllers which measure the SR MOSFET drain voltage, UCC24636 implements a volt-second balance control method to determine the turn off transition of the SR MOSFET; hence, SR conduction time is independent of the MOSFET RDSON, parasitic inductance or ringing allowing flexibility to designers in component slelction and PCB layout. This control method enables maximum SR conduction time and highest rectifier efficiency for a given MOSFET.
The controller has built in intelligence to detect converter no load operation and automatically enters standby mode. While in standby mode, it disables the SR MOSFET and lowers its bias supply current to 110µA to further reduce overall system standby power consumption. The wide VDD operating range for the controller allows direct bias from the converter output for fixed or variable output voltage designs. This eliminates the need for an auxilliary winding on the main transformer, which simplifies the circuit design and reduces the cost.
Technical documentation
| Type | Title | Date | ||
|---|---|---|---|---|
| * | Data sheet | UCC24636 Synchronous Rectifier (SR) Controller With Ultra-Low Standby Current datasheet (Rev. A) | PDF | HTML | 11 Mar 2016 |
| Application note | UCC24630 and UCC24636 SR-Control Configurations Guide | 18 Dec 2017 | ||
| Application note | Design UCC28704 With UCC24636 (PSR+SR) | 12 Jan 2017 | ||
| Technical article | Biasing an SR controller IC in USB smartphone charging applications | PDF | HTML | 08 Dec 2016 | |
| Technical article | USB chargers then and now: Type-C meets energy efficiency standards | PDF | HTML | 23 Sep 2016 | |
| Analog Design Journal | Agency requirements for stand-by power consumption w/ offline and PoL converters | 26 Jan 2016 | ||
| EVM User's guide | Using the UCC24636EVM | 08 Jan 2016 |
Design & development
For additional terms or required resources, click any title below to view the detail page where available.
UCC24636EVM — UCC24636 Synchronous Rectifier Daughter Board/Evaluation Module
Many TI reference designs include the UCC24636
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| Package | Pins | CAD symbols, footprints & 3D models |
|---|---|---|
| SOT-23 (DBV) | 6 | Ultra Librarian |
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