MCP14E3 datasheet(13/26 Pages) MICROCHIP

13 / 26 page

DS22062B-page 13

MCP14E3/MCP14E4/MCP14E5

FIGURE 4-3:

Enable Timing Waveform.

4.4

Decoupling Capacitors

Careful layout and decoupling capacitors are highly

recommended when using MOSFET drivers. Large

currents are required to charge and discharge

capacitive loads quickly. For example, 2.5A are needed

to charge a 2200 pF load with 18V in 16 ns.

To operate the MOSFET driver over a wide frequency

range with low supply impedance, a ceramic and low

ESR film capacitor are recommended to be placed in

parallel between the driver VDD and GND. A 1.0 µF low

ESR film capacitor and a 0.1 µF ceramic capacitor

should be used. These capacitors should be placed

close to the driver to minimized circuit board parasitics

and provide a local source for the required current.

4.5

PCB Layout Considerations

Proper PCB layout is important in a high current, fast

switching circuit to provide proper device operation and

robustness of design. PCB trace loop area and

inductance should be minimized by the use of ground

planes or trace under MOSFET gate drive signals,

separate analog and power grounds, and local driver

decoupling.

Placing a ground plane beneath the MCP14E3/

MCP14E4/MCP14E5 will help as a radiated noise

shield as well as providing some heat sinking for power

dissipated within the device.

4.6

Power Dissipation

The total internal power dissipation in a MOSFET driver

is the summation of three separate power dissipation

elements.

EQUATION 4-1:

4.6.1

CAPACITIVE LOAD DISSIPATION

The power dissipation caused by a capacitive load is a

direct function of frequency, total capacitive load, and

supply voltage. The power lost in the MOSFET driver

for a complete charging and discharging cycle of a

MOSFET is:

EQUATION 4-2:

TABLE 4-1:

ENABLE PIN LOGIC

MCP14E3

MCP14E4

MCP14E5

ENB_A

ENB_B

IN A

IN B

OUT A

OUT B

OUT A

OUT B

OUT A

OUT B

HHHH

HHH

LLLLL

ENB_x

VDD

OUT x

VEN_H

VEN_L

90%

10%

tD3

tD4

Where:

Total power dissipation

Load power dissipation

Quiescent power dissipation

PCC

Operating power dissipation

Where:

Switching frequency

Total load capacitance

VDD

MOSFET driver supply voltage

MCP14E3 Folha de dados(PDF) 13 Page - Microchip Technology

MCP14E3 Folha de dados(HTML) 13 Page - Microchip Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26

Folha de dados Download

Ligação URL