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
