1、Industry Technology Status

Current automotive GPS positioning terminals are designed for large-scale deployment in 12V/24V vehicle environments. These devices must endure prolonged exposure to wide voltage fluctuations, extreme temperature variations, and complex electromagnetic interference while maintaining low-power standby operation and high-precision positioning signal acquisition. The industry faces three major technical challenges: inadequate compatibility with wide voltage input systems, difficulties in balancing power conversion efficiency with static power consumption, and insufficient precision in battery voltage monitoring and sensor signal conditioning. These issues directly impact terminal operational stability, positioning accuracy, and battery endurance performance.

To address these requirements, Corebai has introduced the CBM2596 wide-voltage-drop DC-DC converter coupled with the CBM8621 high-precision rail-to-rail operational amplifier, delivering standardized and highly reliable core components for automotive GPS positioning terminals.

Principle Block Diagram of Vehicle GPS Positioning Terminal

l DC-DC converter: It performs efficient voltage reduction and stabilization from high-voltage vehicle input to system operating voltage, serving as the core component of the terminal power supply chain. Its performance directly determines the system's wide-voltage compatibility and power conversion efficiency.

l Operational Amplifier (OPA): Responsible for precision signal conditioning including battery voltage sampling and GPS weak signal amplification, ensuring analog signal acquisition accuracy and transmission integrity, which directly impacts terminal power monitoring and positioning performance. In this solution, the CBM2596 and CBM8621 serve as core components for power supply and signal transmission chains respectively, working in tandem to achieve stable power supply and high-precision signal processing for the terminal.

2、Analysis of Core Device Technology

（1）CBM2596 Wide Voltage Drop DC-DC Converter

The CBM2596 is a monolithic buck-switching converter specifically designed for automotive wide-voltage power supply applications. It delivers stable 3A load driving performance with excellent linearity and load regulation capabilities, making it ideal for main power conversion requirements in automotive GPS terminals.

It supports a wide input range of 4.5V to 40V, covering the typical operating voltage range of 9V to 36V for vehicle batteries, and is compatible with both 12V passenger vehicles and 24V commercial vehicle systems. The system offers fixed output configurations of 3.3V,5V, and 12V, as well as adjustable output ranges from 1.23V to 37V, with output voltage tolerance controlled within ±4%. This ensures compliance with power supply voltage requirements for various terminal modules.

The device incorporates a 150kHz fixed-frequency oscillator, simplifying peripheral circuit design and requiring only four external components for system integration. It features TTL-level shutdown capability with a typical static current as low as 100μA in shutdown mode, ideal for low-power standby scenarios after terminal deactivation. Additionally, it integrates periodic current limiting and overheat shutdown protection mechanisms to address abnormal operating conditions such as vehicle load rejection, short circuits, and overheating, thereby enhancing system reliability. The packaging adopts TO-220-5L and TO-263-5L specifications, with a temperature range covering-40℃ to +125℃, meeting automotive-grade environmental compatibility requirements.

（2）CBM8621 High-Precision Rail-to-Rail Operational Amplifier

The CBM8621 is a low-voltage rail-to-rail input/output operational amplifier optimized for automotive precision signal conditioning applications. It is ideal for processing dynamic signal variations from sensors such as G-sensors and analog signal processing tasks including battery voltage monitoring.

The device operates within a power supply voltage range of 2.5V to 5.5V, achieving optimal compatibility with terminal low-voltage power systems. With a typical input offset voltage of 0.7mV and an input bias current as low as 1pA, it minimizes signal acquisition errors, ensuring high precision in battery voltage monitoring and GPS weak signal amplification.

The device features a 7MHz gain bandwidth product and 3.7V/μs voltage swing rate, with a 0.1% accuracy setup time as low as 0.5μs, enabling rapid response to dynamic signal variations while preventing signal distortion and attenuation. Its rail-to-rail input/output architecture significantly enhances signal dynamic range, meeting signal conditioning requirements under low-voltage power supply conditions. The CBM8621S version incorporates shutdown functionality, maintaining power supply current below 1μA during shutdown to further reduce system sleep power consumption. The device demonstrates excellent common-mode rejection ratio (CMRR) and power supply rejection ratio (PSRR), with electrostatic discharge immunity compliant with HBM5000V and MM400V standards. Miniature SOT23-5/SOT23-6 packages are optimized for high-density PCB layouts, operating within a temperature range of-40℃ to +125℃, ensuring stable performance in automotive environments with extreme temperatures and electromagnetic interference.

3、solution selection value

This solution centers on CBM2596 and CBM8621, precisely addressing the power supply and signal processing requirements of in-vehicle GPS positioning terminals, with distinct advantages in B-end product selection.

1. Operating condition adaptability: Wide-pressure input, automotive-grade temperature range, and multiple protection mechanisms ensure compatibility with complex in-vehicle environments, thereby reducing system failure rates.

2. Power management: A two-stage low-power shutdown design ensures balanced energy consumption between normal operation and standby mode, thereby extending battery life.

3. Signal accuracy: Signal conditioning capability with low offset and low bias current, enhancing positioning precision and power monitoring accuracy.

4. Engineering feasibility: Simplified peripheral circuits and standardized packaging reduce R&D design and mass production costs while shortening product development cycles.