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This version (29 May 2018 19:16) was approved by Brandon.The Previously approved version (15 Dec 2017 22:57) is available.Diff

EVAL-CN0196-EB1Z Overview

CN0196 is an H-bridge composed of high power switching MOSFETs that are controlled by low voltage logic signals. The circuit provides a convenient interface between logic signals and the high power bridge. The bridge uses low cost N-channel power MOSFETs for both the high and low sides of the H-bridge. The circuit also provides galvanic isolation between the control side and power side. This circuit can be used in motor control, power conversion with embedded control interface, lighting, audio amplifiers, and uninterruptable power supplies (UPS). Modern microprocessors and microconverters are generally low power and operate on low supply voltages. Source and sink current for 2.5 V CMOS logic outputs ranges from μA to mA . Driving an H-bridge switching 12 V with a 4 A peak current requires the use of carefully selected interface and level translation components, especially if low jitter is needed.

The ADG787 is a low voltage CMOS device that contains two independently selectable single-pole double-throw (SPDT) switches. With a 5 V dc power supply, a voltage as low as 2 V is a valid high input logic voltage. Therefore, the ADG787 provides appropriate level translation from the 2.5 V controlling signal to the 5 V logic level needed to drive the ADuM7234 half-bridge driver.

The ADuM7234 is an isolated, half-bridge gate driver that employs Analog Devices’ iCoupler® technology to provide independent and isolated high-side and low-side outputs making it possible to use N-channel MOSFETs exclusively in the H-bridge. There are several benefits in using N-channel MOSFETs: N-channel MOSFETs typically have one third of the on resistance of P-channel MOSFETs and higher maximum current; they switch faster, thereby reducing power dissipation; and the rise time and fall time is symmetrical.

The 4 A peak drive current of the ADuM7234 ensures that the power MOSFETs can switch on and off very fast, thereby minimizing the power dissipation in the H-bridge stage. The maximum drive current of the H-bridge in this circuit can be up to 85 A, which is limited by the maximum allowable MOSFET current.

The ADuC7061 is a low power, ARM7 based precision analog microcontroller with integrated pulse width modulated (PWM) controllers that have outputs that can be configured to drive an H-bridge after suitable level translation and conditioning.

Equipment Needed

  • PC with a USB port and Windows XP, Windows Vista (32-bit), or Windows 7 (32-bit)
  • EVAL-CN0196-EB1Z circuit evaluation board
  • EVAL-ADuC7061MKZ evaluation board
  • DC supply or battery: +12 V, 10 A
  • Load, such as Coilcraft SER2014-402 power inductor
  • Oscilloscope with current probe

General Setup

  • Connect the controlling signal from EVAL-ADuC7061 and CN0196 according to the jumper configuration found in Connectors and Jumper Configurations section below
  • Connect the jumpers LK1 pin 1 and 2, LK2 pin 2 and 3, LK3 pin 1 and 2 and short LK4 pin
  • Apply +12V power supply to J4 of CN0196 board
  • Connect the USB cable from PC to the USB mini connector on the EVAL-ADuC7061-MKZ board
  • Connect an inductor as a load between OUT1 and OUT2 of J3

Test Setup Functional Block Diagram

Connectors and Jumper Configurations

Description

1. Switch S1: ON state provides an isolated side PWM pulses, OFF states makes the PWM disappears
2. Jumper Link LK1: Shorting pin 1 and 2 sets the Source Terminal of ADG787 to 5V while pin 2 and 3 sets to 0V.
3. Header J1: Provides connection of the controlling signals between EVAL-CN0196-EB1Z and EVAL-ADuC7061MKZ as seen in below table

EVAL-ADuC7061MKZEVAL-CN0196-EB1Z
PWRIN J1-1 +5V_2 J1-1
GND J1-2 GND2 J1-2
PWM1 J2-25 PWM1_I J1-4
PWM0 J2-26 PWM0_I J1-5
DVDD J2-28 +2V5 J1-3

4. Jumper Link LK2: Shorting pin 1 and 2 sets the Source Terminal of ADG787 to 5V while pin 2 and 3 sets to 0V.
5. Jumper Link LK3: If pin 1 and 2 is shorted, disabling the ADUM7234 for under voltage condition is generated on board. Shorting pin 2 and 3 will provide externally disabling the isolator via J1-6 header.
6. Connector J3: See below table

Pin NumberDescription
J3-1 VDD: Power Supply of the load
J3-2 VDD: Power Supply of the load
J3-3 OUT1: Connection of the inductor load
J3-4 OUT2: Connection of the inductor load
J3-5 GND: Ground connection
J3-6 GND: Ground connection

7. Connector J4: Connects +12V power supply and Ground return
8. Connector J2: Connection of an external supply up to +20V if jumper link LK4 is not shorted
9. Jumper link LK4: Shorting this pin sets the VDD voltage to +12V

Software and Driver Installation

It is recommended that you install the CN0196 SDP Evaluation Software to the default directory path C:\Program Files\Analog Devices\CN0196\ and all National Instruments products to C:\Program Files\National Instruments\

  • Follow the on screen prompts to install the software






Downloading Firmware to EVAL-ADuC7061-MKZ

  • Connect the EVAL-ADuC7061-MKZ to the PC using USB cable, then find the COM port assigned to this board in the Device Manager.

  • Open the software ”ARMWSD.exe” located in the ARMWSD folder, or C:\Program Files\Analog Devices\CN0196\ARMWSD\ARMWSD.exe.

  • Click the Configure button, Go to Parts tab and select ADuC7061, go to Comms Tab and set the serial port according to the port number indicated on PC device manager and set the baud rate to 9600 as seen in below image.

  • Change tab to Commands, set the Flash and Run selection according to the image below.

  • After setting the configuration, click “Browse” and select file “PWM Generator for EVAL-CN0196-EB1Z.hex” found in the EVAL-ADuC7061-MKZ Firmware folder. Then click start, and a message tells how to download the firmware, Press S2 on EVAL-ADuC7061-MKZ, and hold it down, and meanwhile click the S1 on EVAL-ADuC7061-MKZ. After the downloading process “Flashing Complete”, Click the Run button.

Using Evaluation Software

Software Front Panel

Description

1. Provides control to the following:

  • Connect: Setting up connection between EVAL-CN0196-EB1Z and EVAL-ADuC7061MKZ
  • Disconnect: Disconnects the hardware
  • STOP APP: Closing the CN0196 Evaluation Software

2. Provides control to the following:

  • PWM Pulse Width: Sets the PWM pulse width up to 12.8ms

Pulse width should be less than half of the Pulse Interval

  • PWM Interval: Sets the PWM interval up to 12.8ms depending on the configured PWM pulse width
  • Start/Stop: Provides continuous and discontinues pulses
  • High Side Shot: When this button is pressed, the PWM waveform will display the Voltage on the high side Mosfets Q1 and Q2
  • Low Side Shot: When this button is pressed, the PWM waveform will display the Voltage on the low side Mosfets Q3 and Q4
  • Reset: Resets all the configuration and hardware connection

3. Displays the PWM waveform (V) vs Time(s) depending on the configuration set on the PWM controls
4. Displays the current status/activity being done in the software
5. Provides control to the following:

  • VDD: Controls the supply voltage up to 20V
  • Inductor: Controls the inductor value up to 100mH to be used as a load

6. Displays the Inductor (A) vs Time(s) waveform

Schematic, PCB Layout, Bill of Materials

EVAL-CN0196-EB1Z Design & Integration Files

  • Schematics
  • PCB Layout
  • Bill of Materials
  • PADS project

End of Document

resources/eval/user-guides/circuits-from-the-lab/cn0196.txt · Last modified: 29 May 2018 19:16 by Brandon