H-Bridge Motor Controller Power Supply Circuit – Reference DesignFebruary 24, 2020 by Paul Shepard
The TN90002 reference design from Nexperia is a full bridge dc-dc converter allowing operation of a brushed dc motor (48V max, 12V min, 5A max). The control circuit operates with input voltages from 12- to 48-V for motors up to 250W.
The key feature of this design is that all electronic functions are designed with automotive qualified Nexperia discretes, MOSFETs and logic components (cost-effective, no microcontroller or software needed).
In addition, this H-bridge motor controller PCB allows the user to choose between three Nexperia MOSFET package options (LFPAK33, LFPAK56D or LFPAK56).
- A switch selects the motor rotation direction.
- Jumpers select one of 3 switching frequencies: 7.8kHz, 15.6kHz or 31.3kHz.
- Two tactile push buttons allow the duty cycle (motor speed) to be increased or decreased. There are 8 steps from 0 to 100% duty cycle. A current limitation protection avoids over current in the motor and MOSFETs (set at approximately 6.5A).
- Power Supply
- Accepts 12V to 48V dc input
- Transient overvoltage protection
- Reverse polarity protection
- Buck converter (12V)
- Linear regulator (5V) for logic devices
- Clock and duty cycle generator
- 4MHz crystal oscillator and frequency divider to create 3 different switching frequencies
- Duty cycle sets by push button inputs to select the duty cycle (0% to 100%)
- 5kHz output is used to supply the charge pump on the driving circuitry block
- Reset function to activate other function when VCC 5V supply is stable
- Dead-time function and PWM enable (over current protection disabling)
- Level shifter
- Direction selection
- Driver circuit
- High-side and low-side drivers to drive 4 MOSFETs of the full bridge
- Charge pump to supply the high-side MOSFETs
- Reservoir and decoupling capacitors
- Snubber on the left MOSFETs (switching MOSFETs)
- Jumper to connect the selected MOSFETs
- Gate drive resistors
- Low-side current measurement
- Overcurrent detection
- Comparator, with voltage reference setting current limit
- PWM reset function reactivating PWM if fault disappears