SPI Connectivity Comes to STMicroelectronics’ New Gate Drivers

Battery-powered products are tasked with more than ever. Power tools need longer runtimes, and cordless appliances need more performance. At the same time, designers are under pressure to reduce component counts, simplify layouts, and improve efficiency. STMicroelectronics is targeting those challenges with two new additions to its STDRIVE102 family of three-phase gate drivers. 

Evaluation board for the STDRIVE102 motor gate-driver family, designed to help engineers develop and optimize three-phase brushless motor control systems.

The STDRIVE102P and STDRIVE102BP add SPI connectivity and programmable gate-drive control while maintaining the low-power characteristics that made the original platform attractive for battery-operated equipment.

Built for Battery-Powered Systems

One of the more notable features of the new devices is their extremely low standby current. ST rates the standby mode at less than 50 nA, helping reduce power consumption when the system is inactive. That makes the devices well suited for products that spend long periods waiting between operating cycles. Power tools, cordless vacuum cleaners, and small appliances are obvious examples.

The gate drivers support supply voltages from 6 V to 50 V and can drive six external N-channel MOSFETs in three-phase brushless motor designs. Source current can be programmed up to 1 A, while sink current reaches 2 A. Combined with programmable gate currents, designers can optimize switching behavior without relying on external gate resistors.

Why the SPI Interface Matters

The biggest change in the new versions is the addition of SPI-based configuration and diagnostics. Engineers can now configure gate currents and operating parameters via software rather than relying solely on fixed hardware settings. Internal registers provide access to diagnostics and device settings, making it easier to tune motor performance and adjust behavior during development.

That flexibility becomes especially useful when designs need to support a range of motor characteristics without major hardware changes. SPI also simplifies diagnostics. Fault conditions and operating status can be monitored through the interface, providing developers with greater visibility into what the driver is doing.

Integration Reduces External Components

Integration is one of the defining characteristics of the STDRIVE102 family. The devices include an onboard charge pump that continuously powers the high-side driver circuitry. This allows operation at PWM duty cycles up to 100% without requiring additional circuitry.

Functional block diagram of the STDRIVE102BP showing integrated power management, analog front-end resources, protection circuitry, and three-phase, gate-driver architecture.

The integrated 12-V LDO powers the low-side drivers and can also supply external loads. A second 3.3-V LDO can power low-voltage components and the embedded analog front end. By pulling these functions directly into the gate driver, ST reduces the amount of supporting hardware needed around the motor-control stage. The result is a simpler design with fewer external components and potentially lower bill-of-materials costs.

The STDRIVE102P combines gate-drive control, integrated power management, SPI configuration, and motor-monitoring functions in a compact architecture.

Integrated Analog and Protection Features

The STDRIVE102BP includes a more advanced analog front end with three programmable-gain amplifiers and three high-speed comparators. The STDRIVE102P uses a simplified version with a single PGA and a single comparator. These resources can be used to monitor motor-phase currents through shunt resistors and to detect overcurrent conditions. Individual blocks can also be disabled when not needed to reduce power consumption.

Protection features are extensive. The devices include undervoltage lockout on multiple supply rails, thermal shutdown, and drain-source voltage monitoring on both high-side and low-side MOSFETs. The BP version adds a dedicated fault indicator pin, making it easier to identify supply-related issues.

Designed for Modern Motor Control

The new drivers fit into a broader trend toward smarter motor control hardware. More functionality is being integrated directly into the driver itself instead of relying on multiple discrete components, including power management, monitoring, diagnostics, and configuration.

Devices like the STDRIVE102P and STDRIVE102BP demonstrate how much capability can now be consolidated into a single component as motor control systems continue to evolve. For designers balancing efficiency, board space, and battery life, that level of integration can simplify development while providing greater flexibility throughout the design cycle.