PolyZen Device Helps Protect DC Power Ports

Page Contents:   [ Featured Products | Datasheets | Application Notes | Buy Now ]

Raychem Circuit Protection recently introduced the PolyZen™ device to help provide DC power port protection for portable electronics and systems using barrel jacks for power input. This single device solution helps provide overvoltage protection, transient suppression, reverse bias protection and overcurrent protection.

The most cost effective way to implement a power bus for portable electronics is with a standard DC barrel jack. However, because this connector is inexpensive and thus commonly used, the user may accidentally connect to a wrong power supply at home or while traveling, generating an ‘overvoltage’ or reverse bias fault.

Faults may also occur when using universal power supplies that are sold with a variety of connectors. These devices allow the user to dial in the voltage to levels as high as 24V, as well as switch polarity.

Custom keyed power connectors can mitigate the risk of charger induced failure, but they are expensive to tool, and with the proliferation of portable devices and universal power supplies, they are often easily defeated.

Also, custom connectors do nothing to protect against “dirty” third-party supplies and related voltage transients. Transient protection is especially critical when designing peripherals that may be powered off computer buses and automotive power buses.

 

 

PolyZen Device – How It Works
The polymer enhanced Zener diode microassembly consists of a low resistance, precision Zener diode that is thermally coupled to a PPTC (Polymeric Positive Thermal Coefficient) “thermal switch” device. In operation, extended overvoltage or reverse bias conditions will cause the PPTC to “trip” as the diode begins to heat up.

A “trip event” causes the PPTC “thermal switch” to transition from a low to high resistance state, helping protect downstream electronics by generating a series element voltage drop. Also, by limiting the current, it helps to prevent Zener diode failure due to thermal runaway.

PolyZen devices help lock out inappropriate power supplies and are also effective at clamping and smoothing inductive voltage spikes. In response to an inductive spike, the Zener diode element shunts current to ground until the voltage is reduced to the normal operating range.

In the case of connecting an incorrect voltage power supply, the device clamps the voltage, shunts excess power to ground and eventually locks out the power supply.

The relatively flat voltage vs. current response of the PolyZen device helps clamp the output voltage, even when input voltage and source currents vary. The device’s unique ability to withstand high in-rush currents makes it suitable to help protect portable electronics and other low power DC devices.

 

FEATURES Helps prevent warranty returns and customer complaints resulting from power bus-related incidents Helps shield downstream electronics from overvoltage and negative bias conditions Helps reduce design costs with single component placement and minimal heat sink requirements   BENEFITS Helps shield downstream electronics from overvoltage and reverse bias Trip events shut out overvoltage and reverse bias sources Analog nature of trip events minimize upstream inductive spikes Helps reduce design costs with single component placement and minimal heat sinking requirements

APPLICATIONS Cell phones PDAs MP3 players Digital cameras USB hubs Printers Scanners Hard drives DVD players Desk phones PBX phones

 

 

Part Number	VZ (V) Typical	IZT (A)	IHOLD @ 20ºC (A)	R Typ (Ohms)	R1MAX (Ohms)	VINT Max @ 3A (V)	IFLT Max (A)	Power Dissipation (W)
ZEN056V130A24LS	5.6	0.1	1.3	0.12	0.16	24	+10 / -40	0.7
*ZEN065V130A24LS Coming Soon	6.5	0.1	1.3	0.12	0.16	24	TBD / -40	0.7
*ZEN098V130A24LS Coming Soon	9.8	0.1	1.3	0.12	0.16	24	TBD / -40	0.7
ZEN132V130A24LS	13.4	0.1	1.3	0.12	0.16	24	+3 / -40	0.7
*ZEN164V130A24LS Coming Soon	16.4	0.1	1.3	0.12	0.16	24	TBD / -40	0.7

 

Request a FREE sample

 

 Application Notes

Title	Download
Portable Electronics
Automotive Electronics

 

 

 Featured Products

Part Number		Description	Data Sheet	App. Notes
ZEN056V130A24LS		Polymer Protected, Precision Zener Diodes

refers to New Product Introduction