A DC-DC converter (also known as a direct-current-to-direct-current converter) is a power management device that achieves DC voltage conversion through semiconductor switching technology. It is primarily used in power electronics, communication equipment, automotive electronics, and industrial control applications. Its core functions include step-up, step-down, polarity conversion, and voltage stabilization, adapting to various power supply systems such as batteries and mains electricity. The device consists of a control chip, switching elements (MOSFET/IGBT), energy storage inductors, and filter capacitors, utilizing Pulse Width Modulation (PWM) or Pulse Frequency Modulation (PFM) technology to regulate output voltage. Based on topology, it is categorized into four main types: buck, boost, buck-boost, and isolated. It features high efficiency (70%-95%), miniaturization, and multiple circuit protection mechanisms [1-2]. Typical applications include high-voltage power conversion for electric vehicles, power supply for portable devices, and voltage matching in renewable energy systems. Technological development focuses on high-frequency operation, integration, and intelligent control. A DC-DC converter is a device that transforms electrical energy from one voltage level to another within a direct current circuit.
DC-DC represents a newly developed miniaturized power switching module. It employs microelectronics technology to integrate small surface-mount integrated circuits with miniature electronic components into a single unit. The use of DC-DC power modules simplifies power circuit design, shortens development cycles, and achieves optimal performance metrics. They find extensive application in various digital meters and smart instruments. DC-DC power modules are widely used in power electronics, military, scientific research, industrial control equipment, communication devices, instrumentation, switching equipment, access devices, mobile communications, routers, and other communication fields, as well as in industrial control, automotive electronics, and aerospace sectors. The adoption of modular power systems offers advantages such as short design cycles, high reliability, and easy system upgrades, driving increasingly widespread application of power modules. Particularly in recent years, fueled by rapid growth in data services and the continuous expansion of distributed power supply systems, the growth rate of power modules has surpassed that of primary power supplies. With advancements in semiconductor processes, packaging technologies, and the extensive use of high-frequency soft switching, power modules now deliver greater power density, higher conversion efficiency, and simpler implementation. DC/DC converters are switch-mode power supply chips that utilize the energy storage properties of capacitors and inductors. Through high-frequency switching actions controlled by switches (such as MOSFETs), input electrical energy is stored in capacitors or inductors. When the switch turns off, this stored energy is released to the load, providing power. The ability to output power or voltage is related to the duty cycle (the ratio of the switch's on-time to its entire switching period). Switching power supplies can be used for both step-up and step-down conversion.
The Buck circuit is a non-isolated DC converter widely used in switching power supplies. It is a DC-DC converter based on inductive energy storage principles, involving fundamental concepts of electromagnetic induction and electrical energy conversion from physics. In a buck circuit, the switching transistor's on/off state is controlled by a variable-duty-cycle PWM wave, converting the DC voltage from the input power supply into an adjustable low-voltage output to meet the power requirements of different circuits. Specifically, when the inductor is in the on state, the current flowing through it converts the magnetic field around the inductor's core into magnetic energy, which is then stored within the inductor. During the off state, the inductor's self-inductance induces a voltage in the magnetic field, converting electromagnetic energy back into electrical energy. This energy is then supplied to the load through the output terminals. Thus, by controlling the switch transistor's on/off states, periodic conversion and regulation of electrical energy between the capacitor and inductor are achieved, ultimately delivering a stable DC output voltage.
Additionally, the capacitor in the BUCK circuit smooths the output voltage. It stores electrical energy during the switch's conduction state and releases it during the cutoff state, thereby smoothing output voltage fluctuations. Simultaneously, to ensure stable output voltage, the BUCK circuit typically employs negative feedback control. By sampling the output voltage and feeding it back to the microcontroller, the microcontroller adjusts the duty cycle of the output PWM waveform. This controls the on-time and off-time of the switching transistor, maintaining the output voltage within a predetermined range. Furthermore, the capacitor in the BUCK circuit smooths the output voltage by storing electrical energy when the switch is on and releasing it when the switch is off, thereby mitigating output voltage fluctuations. Simultaneously, to ensure stable output voltage, BUCK circuits typically employ negative feedback control. By sampling the output voltage and feeding it back to the microcontroller, the microcontroller adjusts the duty cycle of the output PWM waveform. This controls the on-time and off-time of the switching transistor, maintaining the output voltage within a predetermined range.
A DC/DC buck converter is a power management device that achieves voltage conversion through high-frequency switching technology. Its core function is to convert an input DC voltage into a lower DC output voltage. Its operating principle is based on switching power supply technology, regulating the output voltage by controlling the on-time and off-time (duty cycle) of the switching element (e.g., MOSFET). ‌12 Core Principle DC/DC buck converters achieve voltage conversion through high-frequency switching actions (e.g., MOSFET conduction and cutoff). During conduction, the input voltage supplies power to the load via the inductor while charging the capacitor; during cutoff, the inductor continues supplying power to the load through the diode while the capacitor discharges energy. Adjusting the switching duty cycle controls the output voltage. ‌13 Key Characteristics
High Efficiency: Efficiency ranges from 70% to 95%, suitable for electric vehicles, portable devices, and similar applications. ‌2 Topology: Includes buck (step-down), isolated, and other types to support diverse application requirements. ‌24 Feedback Mechanism: Utilizes negative feedback regulation technology to monitor output voltage in real-time and adjust the duty cycle, ensuring voltage stability. ‌3 Application Scenarios‌ Electric Vehicles‌: Converts high-voltage power from batteries to low-voltage system requirements. ‌25 Portable Devices‌: Enables battery voltage adaptation for smartphones, laptops, etc. ‌2 Industrial Control‌: Supplies power to precision instruments.
The operating principle of DC/DC driver power supplies involves these key steps: Input DC voltage is converted into pulsed voltage via switching power devices. The pulsed voltage is smoothed through a filter circuit to produce a stable output voltage. The control loop monitors the output voltage and compares it with the setpoint. By adjusting the switching frequency and duty cycle, the output voltage is maintained within the specified range. DC/DC driver power supplies offer numerous advantages over traditional power supplies like linear regulators: High Efficiency: Utilizing switching regulation enables more efficient energy transfer and higher power conversion efficiency. Stability: The control loop continuously monitors output voltage to maintain stability. Flexibility: Capable of various voltage conversion functions such as step-up, step-down, and reverse output as required. Adaptability: Suitable for diverse electronic devices and systems, providing flexible power support.
DC/DC driver power supplies find extensive applications across the electronics field, primarily including but not limited to:
Communication Equipment: Providing stable power support in wireless communication base stations, network devices, etc. Industrial Control: Ensures proper operation in industrial control equipment and sensors. Automotive Electronics: Delivers power conversion for automotive systems like onboard chargers and infotainment systems. New Energy Sector: Facilitates voltage conversion and energy transmission in solar, wind, and other renewable energy conversion systems.