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 micro converters 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.
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
|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
|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
1. Provides control to the following:
2. Provides control to the following:
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:
6. Displays the Inductor (A) vs Time(s) waveform
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