LM43600PWP Application Field and Working Principle

The LM43600PWP is a monolithic, adjustable, pulse-width modulation (PWM) switching regulator in the DC switch regulator family of the PMIC (Power Management IC) voltage regulator. LM43600PWP is designed to efficiently convert an input of 4.5V–17V to an adjustable output, and is ideal for applications such as cellphones, PDAs, DVD players, GPS systems, gaming consoles, and other handheld products.

The LM43600PWP combines a high speed PWM converter with a low dropout regulated output and internal power MOSFET and synchronous rectifier. It offers an output voltage adjustable range of 0.5V to 6V, with a maximum output current up to 2A and switching frequency range of 300kHz to 1.2MHz. Its internal control algorithm includes several unique features such as dynamic voltage scaling, soft-start, and frequency agility that optimizes efficiency by reducing switching losses. It also features integrated low on-resistance MOSFETs, which ensure efficient switching and minimize losses.

Working principle

The LM43600PWP is based on a pulse-width modulating (PWM) switching regulator circuit using the hysteretic topology. At each cycle, the error amplifier compares an internal reference voltage with a feedback voltage, and then activates a comparator. The comparator activates the PWM controller to produce a square wave signal, which is supplied to the main output switch. When the voltage level at the drains of the main output switch exceeds the input voltage level, it triggers the internal synchronous rectifier and transfers the output current.

At each cycle, the LM43600PWP gradually adjusts the output voltage to approach the desired output voltage by controlling the duty cycle of the internal main output switch. As the external output capacitor is self-discharging, the output adjusts accordingly. Also, the LM43600PWP features an internal voltage detector circuit, which senses the presence of an output overvoltage by measuring the voltages across the main output switches. If an overvoltage is detected, the circuit will reduce its switching frequency until the output voltage is brought back within its specified operating range.

Conclusion

The LM43600PWP is a monolithic switching DC-DC regulator from PMIC (Power Management IC) voltage regulator family, designed to efficiently convert an input of 4.5V–17V to an adjustable output. The integrated PWM controller, MOSFETs and synchronous rectifier enable it to provide a low dropout regulated output at a switching frequency range of 300kHz to 1.2MHz, while featuring dynamic voltage scaling, soft-start, and frequency agility to optimize efficiency and minimize losses. The LM43600PWP is ideal for applications such as cellphones, PDAs, DVD players, GPS systems, gaming consoles, and other handheld products.