Correspondingly, power management chips are classified in these aspects, such as linear power supply chips, voltage reference chips, switching power supply chips, LCD driver chips, LED driver chips, voltage detection chips, and battery charging management chips. Below is a brief introduction to the main types and applications of power management chips. If the designed circuit requires high noise and ripple suppression, a small PCB footprint (e.g., mobile phones), and the power supply cannot use inductors (e.g., mobile phones), and needs instantaneous calibration and output status self-test functions, low regulator voltage drop and power consumption, low circuit cost, and a simple solution, then a linear power supply is the most appropriate choice. This type of power supply incorporates the following technologies: a precise voltage reference, high-performance, low-noise operational amplifiers, low-dropout regulators, and low quiescent current. In low-power supply, operational amplifier negative power supply, and LCD/LED driver applications, capacitor-based switching power supply chips, commonly known as charge pumps, are often used.
Many chip products are based on the charge pump principle, such as the AAT3113. This is a white LED driver chip composed of a low-noise, constant-frequency charge pump DC/DC converter. The AAT3113 uses fractional (1.5×) conversion to improve efficiency. This device drives four LEDs in parallel. The input voltage range is 2.7V to 5.5V, providing approximately 20mA of current to each output. The device also features a thermal management system to protect against short circuits on any output pin. Its embedded soft-start circuit prevents current overshoot during startup. The AAT3113 uses a simple serial control interface for enabling, shutting down, and 32-level logarithmic brightness control. Inductor-based DC/DC chips have the widest range of applications, including PDAs, cameras, backup batteries, portable instruments, miniphones, motor speed control, display biasing, and color adjusters. The main technologies include: BOOST structure current-mode loop stability analysis, BUCK structure voltage-mode loop stability analysis, BUCK structure current-mode loop stability analysis, overcurrent, overtemperature, overvoltage and soft-start protection functions, synchronous rectification technology analysis, and reference voltage technology analysis. Besides basic power conversion chips, power management chips also include power control chips aimed at optimizing power supply. Examples include NiH battery intelligent fast charging chips, lithium-ion battery charging and discharging management chips, lithium-ion battery overvoltage, overcurrent, overtemperature, and short-circuit protection chips; chips that manage switching between line power and backup batteries; USB power management chips; charge pumps; multi-channel LDO power supply; power-on sequence control; multiple protections; and complex power chips for battery charging and discharging management. This is especially relevant in consumer electronics. For example, portable DVDs, mobile phones, and digital cameras often only require one or two power management chips to provide complex multi-channel power, maximizing system performance.
The more functions and higher the performance of electronic devices, the more complex their structure, technology, and systems become. This makes it increasingly difficult and expensive for traditional analog power management ICs to meet the overall power management requirements of the system. The core of a digital controller mainly consists of three special modules: an anti-aliasing filter, an analog-to-digital converter (ADC), and a digital pulse width modulator (DPWM). To achieve performance comparable to analog control architectures, high-resolution, high-speed, and linear ADCs, as well as high-resolution, high-speed PWM circuit designs, are essential. The ADC resolution must ensure that the error is within the allowable range of output voltage variation; the lower the required output voltage ripple, the higher the resolution requirement for the ADC. Simultaneously, because anti-aliasing filters and pipelined or SAR ADCs introduce loop delays, high sampling rate ADCs are urgently needed. Analog controllers have inherent limitations on the possible pulse widths they can generate, while DPWM can produce a discrete and finite set of PWM widths. From the perspective of the output in a steady state, only one discrete output voltage is possible. Since DPWM is part of the feedback loop, its resolution must be high enough to prevent the output from displaying well-known limiting cycles. The minimum number of bits required to prevent the display of any limit cycle values depends on the topology, output voltage, and ADC resolution. Meanwhile, the system's loop stability is adjusted by a PI or PID controller.
The future of power management chips looks promising. Through the development of new processes, packaging, and circuit design technologies, even higher-performance devices will emerge, improving power density, extending battery life, reducing electromagnetic interference, enhancing power and signal integrity, and improving system security, thus empowering engineers worldwide to innovate.
