POWER AND LINEAR IC SOLUTIONS

Integrated Half Bridges Suit Automotive Motor Drives

Infineon’s NovalithIC™ devices are high-current, low-ohmic and protected half bridges supplied in a single package for use in motor drive applications in automotive and other demanding environments, providing a PWM capability of up to 25kHz. The devices integrate three chips in a single package: p- (high-side) and n-channel (low-side) MOSFETs and a driver IC.



The devices – the BTS7930B, BTS7960B and BTS7970B – can be used in combination to build half-bridge, H-bridge and three-phase bridge configurations to drive BrushLess DC (BLDC) and DC brush motors for use in high-current applications such as electric car windows, wipers and sunroofs. The NovalithIC family is designed for switching frequencies of up to 25kHz (out of the acoustic range) and implements active freewheeling, actively opening the appropriate FET rather than using the body diode for freewheeling, to reduce power dissipation in the device.

Power dissipation is further reduced by the inclusion of a switched current limitation mode that temporarily disables the FET that detects overcurrent while enabling the other FET for active freewheeling. Unlike most other devices, current limitation is a standard operating mode in NovalithIC devices.

The use of a half-bridge structure spreads power dissipation across two packages when compared to conventional H-bridges, reducing the device’s thermal load and increasing layout flexibility. Available with typical current limitation ratings of 30A, 43A and 68A, and with low path resistance down to 16mΩ, NovalithIC devices can serve high current requirements in a small package.

NovalithIC devices implement integrated over-current, over-voltage and over-temperature protection, minimising the number of external components required in most designs. An analogue current sense is available, requiring no shunt resistance for block detection and current control and therefore further reducing component count.

Because NovalithIC devices do not need a charge pump structure, they provide inherently superior ElectroMagnetic Compatibility (EMC). A variable slew rate adjustment allows the designer to balance further the requirements of emissions and switching losses.

The control IC features logic level inputs, allowing direct connection to a microprocessor. Status flag diagnosis provides error detection with direct feedback to the microcontroller. The entire assembly consumes a quiescent current of just 7µA, significantly extending battery life.


Block Diagram of a NovalithIC

Features

• Integrated protected half-bridges
• Typical current limitations at 30A, 43A and 68A (LS@25°C)
• Integrated high- and low-side driver and controller
• Very low path resistance down to 16mΩ (typ. @25°C)
• Low quiescent current: typically 7µA at 25°C
• PWM (Pulse-Width Modulation) capability of up to 25kHz with active freewheeling
• Switched mode current limitation for reduced power dissipation in overcurrent (~10kHz PWM)
• Status flag diagnosis with current sense capability
• Overtemperature shut down with latch behaviour
• Overvoltage lockout and undervoltage shut down
• Driver circuit with logic level inputs
• Adjustable slew rates for optimised EMI

Applications

• Automotive
  • Power windows
  • Sunroofs
  • Central locking
  • Seat positioning
  • Wipers
  • Washer pumps
  • Four-wheel transmission
  • Clutches
  • Cooling fans
• Industrial
  • Automation
  • Robotics
  • Power tools
  • Vending machines

For further information, including the NovalithIC Datasheet, please click here