Application Design Center - Dishwasher

OV/OC Protection of DC Input

Solutions

• TVS Diode Arrays
• Leaded and Cartridge
• Resettable PPTC

Design Notes:

Protection Application:

For LCD back lighter and microprocessor power, a DC voltage (typically in the range of 5VDC to 18VDC) will be supplied. The electrical threats include lightning surges, ESD and overcurrent conditions (short circuit or overload).

Solution Description:

As shown at the left, a fuse or PTC can be used for short circuit and overload current conditions. For surge and ESD protection, TVS diode (e.g. P4KE or P4SMA series) can be used.

Companion Solutions:

Note that the magnitude of the surge transient should be understood as this can point to alternative solutions. For example, if more severe surges are expected, then C-III or UltraMOV varistors or higher-rated diodes (e.g. 600W, 1,500W) can be selected. If the only threat is expected to be ESD, then multilayer chip varistors can be selected.

Regulatory Issues:

If ESD is a concern, the IEC 61000-4-2 can be consulted to find information on the test method and transient waveform that should be used.

Unique Features:

Does not apply.

Application Warnings:

Does not apply.