Signal Consulting, LLC 

Model Si20HPB4-50V-20A-HB2 

50V-20A High Power H-Bridge with Integrated Half-Brick Finned Heat Sink for Bidirectional DC Motor Control





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Si20HPB4-50V-20A-HB2 Features:

Max. Continuous Load Current: 20A with Heat Sink (as  shown ).
Max. Load Current for 2 sec: 50A with Heat Sink (as shown).

Overall Dimensions: 2.4”x2.35”x2.30”, (62 x 59 x 57 mm).

Typical Operating Temperature:  450C at 15A with the board mounted on a (2.4”x2.3”x0.9”) Finned Heat-Sink and exposed to air at 250C (shown on photograph). Or 450C at 20A with the Finned Heat-Sink Bolted to a Metal Frame.

Voltage Requirements: A Single DC Source (unregulated and unfiltered). Any voltage from 9V to 50 Volts ( from Pin +P to Pin -P).

Control Type: Active High, (0 to 5V)

Typical Power Efficiency: 98.5% at full-load (50V and 20A).

Load Isolation: The Load Must be Isolated for the Power Source.
Components Type: 100% Solid State, NO Relays

On Board: 
Filter Capacitors.
VTS diodes.
Snubber Circuit.


    For Details, Download the  Si20HPB4-50V-20A-HB2-5   Manual


The Si20HPB4-50V-20A-HB2 is an efficient high-power H-bridge that works over a wide range of source voltages (9V to 50V) at high continuous load currents (+/-20A max). This board includes an integrated black finned heat-sink (2.4”x 2.3”x0.95") to achieve this impressive performance (as shown on the photograph, above). Higher current values can be attained with more efficient heat sinks. The motor action (as shown on the truth table below) is controlled by the voltages applied to pin F and pin R (relative to pin C) on the Control connector (shown on the application drawing below). These pins are optically isolated from the rest of the power circuit, requiring a minimum input current of 1.5 mA at 3.5V and max input current of 7mA at approx. 9V. An external resistor, (connected in series with each control input F and R) can be used when higher control voltages are required (1kW for 12V, 2.2kW for 24V). 

              Control Input Truth Table (for Control connector)



Motor / Load  Action

LOW = 0 Volts

LOW = 0 Volts

Motor Stop / Load Current OFF

HIGH = 5 Volts

LOW = 0 Volts

Motor Forward / + Load Current

LOW = 0 Volts

HIGH = 5 Volts

Motor Reverse / - Load Current

HIGH = 5 Volts

HIGH = 5 Volts

NOT Recommended*

* When VFC and VRC are HIGH at the same time, the motor will spin forward or reverse depending which control signal arrives first; but no damage will occur to the load, board or the power source.

         The VFC and VRC control lines can be Pulse-Width Modulated (PWM in a range of 0-20k HZ) to vary the average current supplied to a load or to a DC Motor.

           A bicolor LED is used to monitor the load voltage (Forward = Red, Reverse = Green).

 Voltage Requirement: The Si20HPB4 will work with any DC motor in the 9 V to 50 V range. In addition, the power filters are included on this board. Consequently, only unregulated DC input power is required in most applications. Furthermore, the control circuit is optically isolated from the power circuit; rejecting unwanted power glitches.

Frequency Response of the Si20HPB4-50V-20A-HB2

The Si20HPB4 control inputs (VFC, VRC) can be Pulse Width Modulated (PWM with duty-cycle of 0% to 100%) over a wide range of carrier frequencies, as shown on the graph. This plot was obtained with the 2.4” x 2.3” x 0.95” finned heat-sink (as shipped with the unit) placed on a nonmetallic bench top and exposed to 25 degree C air. Improved performance (20A) can be achieved with the heat-sink bolted to a metal frame (- - With Extra Heat Sink).

  Typical Motor Control Application of the Si20HPB4-50V-20A-HB2

 In this bidirectional speed control application,  the motor speed and direction is controlled by 2 external signals connected to pin F (Forward)  and to pin R (Reverse) on the Control connector. These two (0 to +5V , relative pin C) inputs can be Pulse –Width Modulated over a wide Frequency range. These three pins are optically isolated from the power supply and the load.

Warning:  The connecting wires to the Load and the Power Supply must be heavy gauge copper wire (#12 AWG or heavier) to handle the rated current level. In addition, these heavy gauge wires act as a heat sink, protecting the board from overheating.

 Typical Applications: Driver for Bidirectional Variable-Speed  DC Motors, Peltier Effect TE Cells, Heat Pumps, PPDT Solid State Relays.

Si20HPB4-50V-20A-HB2, 50V 20A H-Bridge with Finned Heat Sink for Bidirectional Motor Control                                
Price  $129.00

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Availability: We usually ship in 2-3 business days.



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