ISL6439IB

The ISL6439IB is a DC/DC switching controller designed to primarily regulate the output of DC/DC power architectures. The device has a low operating current, allowing it to be used in multiple applications, including 12V automotive supplies, 5V and 3.3V ATX supplies, telecom systems, battery operated systems, and laptops. The ISL6439IB is a low-power, low-cost, universal DC/DC switching controller.

The ISL6439IB employs an advancements phase-shift full-bridge converter topology, allowing it to achieve excellent regulation of DC/DC outputs, while maximizing efficiency. This topology is extremely flexible and offers the designer many options on output voltage, load current, and load utilization. Also, the adjustable output voltage scale on the ISL6439IB makes it suitable for multiple applications, from point of load applications to motor control.

Features

• Input supply voltage range of 6 to 18V
• Open loop regulation at light and heavy loads
• Choice of synchronous or non-synchronous operation
• Integrated low-side power MOSFET
• Stable with small output capacitors (1x330uF)
• Adjustable switching frequency
• Over-voltage, under-voltage, and current limit protections
• Internally compensated

Applications

• 12V automotive supplies
• 5V and 3.3V ATX supplies
• Telecom systems
• Battery operated systems
• Laptops
• Point of load applications
• Motor control
• DC/DC power architectures

Working Principle

The ISL6439IB is a low-power, low-cost, universal DC/DC switching controller. Its working principle is based on an advancements phase-shift full-bridge converter topology. This topology is extremely flexible and offers the designer many options for output voltage, load current, and load utilization.

The ISL6439IB is designed to operate as a buck, boost, or buck-boost converter. The device functions by producing two 50% duty cycle waveforms, which switch at a frequency determined by an external resistor or RC network. When the control line is high, the output voltage is determined by the ratio of an external resistor and an internal reference, such that a high voltage results in a lower output voltage. When the control line is low, the output voltage is determined by the ratio of the resistors in the voltage divider, such that a lower voltage results in a higher output voltage.

The ISL6439IB also offers adjustable over-voltage and under-voltage protection, as well as adjustable current limiting. The device includes an internal low-side power MOSFET, allowing the designer to limit the output current without the need for additional external FETs and components, resulting in a low overall system cost. The ISL6439IB also integrates a soft-start function, allowing it to gradually ramp up the output current to reduce the in-rush current during start-up.

Conclusion

The ISL6439IB is a low-power, low-cost, universal DC/DC switching controller designed for a variety of applications, including 12V automotive supplies, 5V and 3.3V ATX supplies, telecom systems, battery operated systems, and laptops. The device has a low operating current and employs an advancements phase-shift full-bridge converter topology, allowing it to achieve excellent regulation of DC/DC outputs, while maximizing efficiency.