ISL6526CB-T

ISL6526CB-T Application Field and Working Principle

The application field of the ISL6526CB-T, a DC-DC synchronous buck converter, is principally single and dual output steady-state converters. It supports up to 18A continuous current in both conventional and synchronous buck-boost operation. Moreover, it offers a variety of preset VCC, VTT voltages, as well as high-speed PWM current-mode control with low-side MOSFET current sensing.

The ISL6526CB-T is ideal for powering FPGA and ASIC circuits, along with providing small footprint, low EMI, low power overhead and outstanding transient response while requires locking in 200 nanoseconds or less.

Besides, the gate drive capability offers a wide range of gate drive for low-side FETs, as well as SPICE-level modeling of input and output impedance, thermal and di/dt immunity.

Working principles

The ISL6526CB-T works in the same manner as a buck converter. It consists of two transistors (usually MOSFETs) connected in a series configuration. An input voltage is applied to the transistors’ gate, while a resistor connected to the drain is used to control the amount of current passing through the transistor. The output is obtained by connecting the output of the bottom transistor to the positive side of the load. This helps to regulate the amount of current passing through the MOSFET, thus controlling the switching speed and thus the buck converter’s output voltage.

The main components of a DC-DC synchronous buck converter are its control block and power stage. The control block contains feedback control circuitry which produces a reference voltage that is proportional to the output voltage. This reference voltage is then compared to a feedback voltage taken at the output side of the power stage. The difference between the two voltages is sensed by the error amplifier and then passed to the PWM circuit. The PWM circuitry then encodes the error signal into pulses which are sent to the power stage. The power stage then dissipates or draws the energy as a function of the pulses sent to it, thus controlling the output voltage.

In some switch controllers, such as the ISL6526CB-T, a current-mode control is used to improve output accuracy and response time, thereby allowing faster conversion speeds. The advantage of the current-mode over the voltage-mode control is that the current-mode can detect the changes in the load current, allowing the system to respond more quickly and accurately to changes in the load current. The current-mode can also detect the changes in the input current, allowing the system to maintain a constant output voltage even if the input voltage changes.

Conclusion

The ISL6526CB-T is a highly efficient DC-DC synchronous buck converter, ideal for powering FPGA and ASIC circuits, offering a variety of preset voltages and other features. Its main working principle is that of a regular buck converter, while the current-mode control allows faster conversion speeds and better accuracy.