Parallelable, Secondary-Side Synchronous Rectifier Driver and Feedback-Generator Controller ICs

The MAX5058/MAX5059 enable secondary-side synchronous rectification in isolated power supplies using widely available power MOSFETs. These devices facilitate the commutation of the secondary-side MOSFETs by providing a clean gate-drive signal that is synchronized to the power MOSFET switching in the primary side of the isolation transformer. The MAX5058/MAX5059 complement the MAX5051 and MAX5042/MAX5043 primary-side PWM ICs and enable the design of high-efficiency, synchronously rectified, isolated power supplies. Simultaneous conduction of the primary side and the freewheeling synchronous rectifier MOSFET is avoided by having a look-ahead signal (before the primary-side MOSFETs turn ON), thus eliminating large current spikes resulting from a shorted transformer secondary.

An on-board error amplifier with a versatile current reference output enables virtually unlimited possibilities in reference-voltage generation. Reference voltage for the error amplifier is generated by connecting an appropriate resistor to this output.

Low on-resistance margining MOSFETs integrated on-chip allow for implementation of a margining circuit without the use of external switches. The MAX5058 provides a 5V LDO output for logic-level MOSFETs, while the MAX5059 provides a 10V LDO output for conventional 10V MOSFETs.

The MAX5058/MAX5059 are designed to enable paralleling of multiple power supplies for accurate current sharing using a simple 2-wire, differential, current-share bus. Parallelability enables expansion of the power capabilities and simplifies thermal management in high-output-current applications. When used with the MAX5051, the primaries can also be synchronized and operated 180 degrees out of phase.

The MAX5058/MAX5059 are available in a 28-pin thermally enhanced TSSOP package and operate over a wide -40°C to +125°C temperature range.

Warning: The MAX5058/MAX5059 are designed to work in circuits that contain high voltages. Exercise caution.

Applications

* ±48V Power-Supply Modules * ±48V/±12V Server Power Supplies * Industrial Power Supplies * Isolated Networking Power Supplies * Isolated Telecom Power Supplies

* Clean Drive Waveforms for Synchronous MOSFETs

* Utilization of a Look-Ahead Signal from the Primary for Proper Turn-On/Turn-Off Times

* Synchronous Rectifier Drivers Capable of Sourcing and Sinking Up to 2A Peak Current

* Internal Gate-Voltage Regulator for 5V (MAX5058) or 10V (MAX5059) Gate-Drive Voltage

* Internal Error Amplifier

* Accurate Differential Current-Share/Force Circuit Allows Paralleling of Several Power Supplies for High Output Current

* Internal Remote Voltage-Sense Amplifier

* Flexible Reference-Voltage Generation

* Output Voltage Regulation Down to 0.5V

* Low Quiescent Current Consumption of 2.5mA

* Integrated Digital Output Margining Circuit Saves External Parts and Board Space

* 30ns Propagation Delay Time from Pulse Input to Output

* Automatic Detection of Discontinuous Current Conduction and Turn-Off of the Freewheeling MOSFET

* High Efficiency at Low Output Currents and Reverse-Current Protection

* Open-Drain Overtemperature Warning Flag

* 28-Pin Thermally Enhanced TSSOP Package