ITPC20150003U1 - REDUNDANT SYSTEM FOR CONTROL OF POWER SWICHING CIRCUITS WITH ANOMALY SIGNAL LED - Google Patents

Description

DESCRIPTION of the UTILITY MODEL having as TITLE:

"Redundant system for the control of switching power circuits with led of

anomaly signaling "

The following circuit topology aims to increase the reliability of the

switching power circuits, by means of the insertion of a redundant system which

it is activated in case of failure of the main circuit.

The user is informed of the circuit anomaly by visual signaling and / or by

by sending a remote control signal.

The redundant system comes into operation only in the event of an anomaly of the

switching circuit.

With reference to the main drawing, suppose that a Mosfet failure occurs

switching Q1, such as to short circuit the drain with the source. In this case, the

drain current will flow in fuse F (fast type), with such an intensity as to cause it

the opening. In this way the Mosfet switching Q2 will automatically start,

which until that moment was inhibited by the presence of the fuse. The opening of the latter

it also involves the lighting of the visual signaling LED. Electronic components

called RI, Cl, D and C2 have a dual function: as a snubber network and as a capacitive drop power supply for the LED diode, whose current is limited by the presence of R2.

Particular care must be taken in sizing the tripping current of the fuse F, in particular the parameter l <2> t of the same must be less than the l <2> t of the main fuse placed upstream of the whole switching circuit, to guarantee the tripping selectivity of the fuses on short-circuit.

Current switching circuits, applied to power supply systems (power supplies for electronic devices, electronic ballasts, regulators, stabilizers, inverters, etc.), have a typically common circuit configuration: oscillator circuit (buckbust, chopper, flyback, SMPS), a transformer generally driven in pull-up and a Mosfet that acts as an electronic switch for the transformer.

Generally the major failures concern precisely the power Mosfets, since these are subject to significant thermal rises, relatively high impulse currents and voltages between drain and source that often approach the break-down threshold.

Often the fault consists of a short circuit between the drain and the source. This implies the intervention of the protection fuse placed upstream of the mains input line and consequently the power supply is switched off. The system presented here tries to overcome this problem, by inserting a second Mosfet to replace the one that is short-circuited.

The advantage of this solution is that the visual and / or remote signals allow the operator to replace the main Mosfet while ensuring the continuity of system operation.

The system presented here cannot work if the failure of the main Mosfet consists of a short circuit between the drain and the gate or between the gate and the source or a short circuit between all three electrodes of the Mosfet.

The advantages of the redundant system for controlling power switching circuits with anomaly signaling LEDs compared to current circuits on the market are:

• Greater reliability

• Longer useful life

• Visual signaling of the presence of a malfunction of the main Mosfet

• The continuity of the service carried out by the circuit even in the presence of a fault in the main Mosfet

Claims (4)

CLAIMS 1) Protection systems consisting of a series of two or more Mosfets with exclusion fuse and fault display through luminous and / or remote signals. 2) Redundancy systems applied to the power drivers of switching transformers. 3) Redundancy systems that use two or more Mosfets in parallel with protection fuses in series. 4) Protection and redundancy systems using Mosfet, BJT or IGBT placed together in series or in parallel.