EK027 DC Motor driver Bipolar
Part.no: 41017903
EK027 is a motor driver for most common DC motors and can control a motor from standstill to full speed in both directions (forward and reverse).
Speed and direction are controlled by the potentiometer or an external control voltage. When the potentiometer is turned left, the motor runs counter-clockwise. When turned right, the motor runs clockwise. A center region brakes the motor to a standstill. The center dead zone can be modified by replacing resistor R6.
The external control voltage input is summed with the potentiometer voltage, allowing speed and direction to be controlled by sources such as potentiometers, light sensors, buttons, or limit switches.
The control circuit is built around four op-amps. Two amplifiers form a voltage-controlled oscillator that generates a triangle wave. The other two amplifiers are configured as a window comparator. The comparator compares the oscillator voltage against the reference voltages generated by the resistor divider (R6, R7, and R8). By shifting the triangle wave up or down with the potentiometer or control voltage, either positive or negative pulses are passed through. When the control voltage is at center, neither comparator output is active and the motor is stationary. The comparator outputs are used to drive four power FET transistors configured as an H-bridge, which in turn drives the motor in either direction.
The oscillator frequency can be set in two steps by jumpering the pins marked "Slow" or "Fast". In slow mode the motor is driven at a PWM frequency of 266Hz, and in fast mode at 16kHz. Lower frequency works better for larger, higher-current motors, while higher frequency works better for small motors.
The entire board runs from a single supply voltage connected to the terminals marked "V−" and "V+". A low-pass filter (R19 and C6) is included to prevent motor noise from affecting the amplifier circuit. The filtered voltage is available at the connectors adjacent to the control voltage input and can be used as a reference for external sensors or potentiometers.
The power supply and motor terminals are compatible with standard screw terminals or pluggable screw terminals. Wires can also be soldered directly to the board.
| Compatible screw terminals: | |
|---|---|
| Screw terminal 5mm 2-pin | 40210002 |
| Screw terminal pluggable 5.08mm 2-pin | 40210011 |
| PCB header 5.08mm 2-pin | 40210021 |
| PCB header 5.08mm 2-pin right-angle | 40210031 |
- Supply voltage: 5 – 15VDC
- Control voltage: 0 - V+
- Maximum load: 5A (requires active cooling)
- PWM frequency: 266Hz or 16kHz
- Dimensions: 76.2 x 50.8mm
- Mounting holes: c-c 71.1 x 45.7mm, ø2.5mm
Component list
| RefDes | Value | Qty. | Part.no. | Marking |
|---|---|---|---|---|
| C1, C3 | El.lyt capacitor 1000uF | 2 | 41017936 | 1000uF |
| C2, C7, C9 | Ceramic capacitor 100nF | 3 | 41016717 | 104 |
| C4 | El.lyt capacitor 10uF | 1 | 40520003 | 10uF |
| C5 | Ceramic capacitor 10nF | 1 | 41017770 | 103 |
| C6 | El.lyt capacitor 220uF | 1 | 41017690 | 220uF |
| D1, D2 | Diode 1N4148 | 2 | 40310010 | |
| D3, D4, D5, D6 | Diode 1N4004 | 4 | 40310004 | |
| D7 | LED 3mm red/green 2-pin | 1 | 40307070 | |
| R1, R2 | Resistor 47kohm | 2 | 40811447 | |
| R3, R4, R16 | Resistor 100kohm | 3 | 40811510 | |
| R5, R7, R8, R9, R10, R11, R12, R15, R17, R18, R20 |
Resistor 10kohm | 11 | 40811410 | |
| R6, R13, R14 | Resistor 4.7kohm | 3 | 40811347 | |
| R19 | Resistor 10ohm | 1 | 40811110 | |
| M1, M4 | Heatsink TO-220 | 2 | 41016259 | |
| T1, T3 | IRF530 FET N-ch | 2 | 40320530 | IRF530N |
| T2, T4 | IRF9530 FET P-ch | 2 | 41015917 | IRF9530N |
| T5, T6 | BC547 NPN | 2 | 40320001 | BC547C |
| U2 | TLC274 | 1 | 40350274 | TLC274CN |
| VR1 | Potentiometer 100kohm | 1 | 40910030 | B100k |
| Screw M3 10mm | 2 | 41010773 | ||
| Hex nut M3 | 2 | 41010787 | ||
| Jumper 2.54mm 2-pin | 1 | 41017254 | ||
| DIL socket 14-pin | 1 | 40410014 | ||
| Pin header 2.54mm 2-pin | 3 | 41001167 |
Assembly guide
Before beginning assembly, check that the PCB is free of damage and scratches. Verify that you have all components to be installed by comparing against the component list.
It is generally easiest to start with the lowest-profile components and work upward by height. IC sockets, resistors, ceramic capacitors, and diodes are installed first. Electrolytic capacitors, connectors, and potentiometers are installed last.
For certain components, correct orientation is critical. Pay attention to the markings on the board.
Interactive assembly guide ↗
Simulation
Oscillator & Comparator ↗
H bridge ↗
Schematic
Drawing
