
Fig. 1
Tri-State H-Bridge using CD4093B CMOS Circuit
Here we look at an improved tri-state H-bridge. This a big improvement over earlier variations.
The goal is circuit theory. To connect to basic microcontrollers operating at 3.3V-5V to a flexible higher voltage circuit.
The voltage range of the circuit based on a CD4093B and an IRF4905 (Q4, Q6) and IRFZ44N (Q5, Q7) MOSFETs ~3-15-volts.
The Schmitt trigger inputs of the CD4093B quad, 2-input NAND gate assures more stable switching. This replaces the CD4011B from earlier circuits.
Q1, Q2, and Q3 are 2N7000 N-channel MOSFETs in a TO-92 package. With their associated 10K pull up resistors provide an easy voltage interface between the microcontroller and CD4093B switching the power MOSFETs Q4-Q7.
This replaced the SN7407 TTL integrated circuit from earlier designs. This also eliminated the use of opto-couplers.
Connections "A" and "B" with "EN" connect directly to the microcontroller or Raspberry Pi IO pins.
Make sure to connect the ground to the microcontroller ground. Connect "*" to the microcontroller 3.3V or 5V power buss.
When "EN" is HIGH motor direction is determined by inputs "A" and "B". The can be connected together and programmed for forward and reverse only. "EN" acts as motor ON-OFF.
As a final note the "EN" connection my require a 1K resistor to ground. This assures the motor is turned off if the IO pin to the Raspberry Pi, etc. isn't LOW during boot up.
- From Basic Digital Circuits to H-Bridge Motor Controls
- Non-Inverting Tri-State Buffer-Switch Demo Circuit
- Review Connecting Digital Logic and Transistors
- Optocouplers for TTL-CMOS Logic Level Shifting
- H-Bridge Schematic with MOSFET Outputs
EN | Input A | Input B | AOUT | BOUT | OUT MODE |
HIGH | HIGH | LOW | 12V | 12V | STOP |
HIGH | HIGH | HIGH | 12V | 0V | FWD |
HIGH | LOW | HIGH | 0V | 0V | BRK |
HIGH | LOW | LOW | 0V | 12V | REV |
LOW | X | X | HiZ | HiZ | OFF |

Fig. 2
CD4093B Quad 2-Input NAND Schmitt Trigger is shown in Fig. 2. Voltage range 3-15-volts. While low power the current sink or source output is low. But this no problem driving MOSFET transistors.
The Schmitt trigger input assures better circuit performance in H-bridge circuits. There is better noise response.
- Tri-State H-Bridge using CD4093B CMOS Circuit
- Simplified CMOS-MOSFET H-Bridge Circuit
- Programming PCF8574P 8-bit I-O Expander with PICAXE, Arduino
- Interfacing Microcontrollers to CMOS and MOSFET Circuits
Return Hobby Electronics Main Page
- TB6600 Stepper Motor Driver with Arduino
- Common Collector Opto-Isolated Bipolar Transistor Switches
- Compare 2N3055 and MJE10005 Transistor Power Switches
- TC4420 MOSFET Driver Replacement Circuits
- Common Collector Opto-Isolated Bipolar Transistor Switches YouTube
- Build TC4420 MOSFET Driver Replacement Circuits
- Compare 2N3055 and MJE10005 Transistor Power Switches
- Pt. 1 TB6600 Stepper Motor Driver with Arduino Hardware
- Pt. 2 Program TB6600 Stepper Motor Driver with Arduino
Related links:
- Hobby Electronics
- Optical Isolation of H-Bridge Motor Controls
- All NPN Transistor H-Bridge Motor Control
- Basic Transistor Driver Circuits for Micro-Controllers
- ULN2003A Darlington Transistor Array with Circuit Examples
- Tutorial Using TIP120 and TIP125 Power Darlington Transistors
- Driving 2N3055-MJ2955 Power Transistors with Darlington Transistors
- Understanding Bipolar Transistor Switches
- N-Channel Power MOSFET Switching Tutorial
- P-Channel Power MOSFET Switch Tutorial
- Build a Transistor H-Bridge Motor Control
- H-Bridge Motor Control with Power MOSFETs
- More Power MOSFET H-Bridge Circuit Examples
- Build a High Power Transistor H-Bridge Motor Control
- H-Bridge Motor Control with Power MOSFETs Updated
- Opto-Isolated Transistor Drivers for Micro-Controllers
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