What is an inductive boost DC/DC converter? I believe many electronic engineers know about inductive boost DC/DC converters because they are used in many circuit designs. Do you know its principle?
The role of the inductor: It is an energy conversion device that converts electrical energy and magnetic field energy into each other. When the MOS switch is closed, the inductor converts electrical energy into magnetic field energy and stores it.
When the MOS is disconnected, the inductor converts the stored magnetic field energy into electric field energy. This energy is superimposed with the input power supply voltage and filtered by diodes and capacitors to obtain a smooth DC voltage to provide to the load.
Since this voltage is formed by the superposition of the input power supply voltage and the magnetic energy of the inductor converted into electrical energy, the output voltage is higher than the input voltage, that is, the boost process is completed.
In the actual circuit, the IC with integrated power MOSFET replaces the mechanical switch, and the on and off of the MOSFET is controlled by the pulse width modulation (PWM) circuit. The output voltage is always determined by the PWM duty cycle. When the duty cycle is 50%, the output voltage is twice the input voltage. Doubling the voltage will make the input current twice the output current. For actual lossy circuits, the input current is slightly higher.
How does the inductor value affect the performance of an inductive boost converter?
Because the inductor value affects the input and output ripple voltage and current, the choice of inductor is critical to the design of an inductive voltage converter. Inductors with low equivalent series resistance values have the best power conversion efficiency. The inductor saturation current rating should be selected to be greater than the circuit's steady-state inductor current peak.
What is an inductive boost DC/DC converter?
In an inductive DC-DC converter circuit, closing the switch causes the current through the inductor to increase. Opening the switch causes current to flow through the diode to the output capacitor. Due to the storage of current from the inductor, the voltage of the output capacitor increases after multiple switching cycles, resulting in an output voltage higher than the input voltage.
Where are inductive boost converters used?
One major application area for inductive boost converters is to power white LEDs, which can provide backlighting for liquid crystal display (LCD) panels in battery-powered systems. They can also be used in general-purpose DC-DC voltage regulators that need to increase voltage.
What factors determine the output voltage of an inductive boost DC-DC converter?
In actual circuits, an IC with an integrated power MOSFET replaces the mechanical switch, and the MOSFET is turned on and off by a pulse width modulation (PWM) circuit. The output voltage is always determined by the PWM duty cycle, and at a duty cycle of 50%, the output voltage is twice the input voltage. Doubling the voltage will cause the input current to be twice the output current, and for actual lossy circuits, the input current is slightly higher.
How to choose the input capacitor of an inductive boost converter IC circuit?
The input of the boost regulator is a triangular voltage waveform, so the input capacitor must be required to reduce input ripple and noise. The amplitude of the ripple is inversely proportional to the size of the input capacitor value, that is, the larger the capacitance, the smaller the ripple.
If the converter load changes little and the output current is small, it is safe to use a small input capacitor. If the converter input and source output are close, small capacitors can also be selected.
If the circuit is required to have little interference with the input voltage source ripple, large capacitors may be required and/or the equivalent series resistance (ESR) may be reduced.
How does the inductor value affect the performance of an inductive boost converter?
The choice of inductor is critical to the design of an inductive voltage converter because the inductor value affects the input and output ripple voltage and current. Inductors with low equivalent series resistance values have the best power conversion efficiency. The inductor saturation current rating should be selected to be greater than the circuit's steady-state inductor current peak.
What factors should be considered when selecting the output capacitor in an inductive boost converter IC circuit?The choice of output capacitor is determined by the output voltage ripple. In most cases, low ESR capacitors such as ceramic and polymer electrolytic capacitors should be used.
If high ESR capacitors are used, the converter frequency compensation needs to be carefully reviewed and additional capacitance may be required at the output circuit.
How to choose the input capacitor of an inductive boost converter IC circuit?
The input of the boost regulator is a triangular voltage waveform, so the input capacitor must be required to reduce input ripple and noise. The amplitude of the ripple is inversely proportional to the size of the input capacitor value, that is, the larger the capacitor value, the smaller the ripple. If the converter load changes are small and the output current is small, it is also safe to use a small input capacitor.
If the converter input is very close to the source output, small capacitors can also be selected. If the circuit is required to have little effect on the input voltage source ripple, large capacitors may be required and/or the equivalent series resistance (ESR) may be reduced.
What factors should be considered when laying out the circuit of an inductive boost converter IC?
First, the input capacitors should be as close to the IC as possible to reduce the copper trace resistance that affects the IC input voltage ripple.
Second, place the output capacitors close to the IC. The length of the copper trace connecting the output capacitors will affect the output voltage ripple. Third, minimize the length of the trace connecting the inductor and the output diode to reduce power dissipation and improve efficiency. Finally, the output feedback resistor should be far away from the inductor to minimize the impact of noise.
What factors should be considered when selecting the output capacitor in an inductive boost converter IC circuit? The choice of output capacitor is determined by the output voltage ripple. In most cases, low ESR capacitors such as ceramic and polymer electrolytic capacitors should be used. If high ESR capacitors are used, the converter frequency compensation needs to be carefully examined and additional capacitors may be required at the output circuit.
