Alarm System - QBAR®
Switch in Series with Load
A QBAR® switch will
reliably activate an alarm (a warning display, a cooling
fan, a not-ready indicator, or any other load that should
be driven during failure) over a wider range of fault
conditions than other switch types.The QBAR®
switch will turn the alarm on when:
- LO on the status output indicates system failure
- +5 V supply is lost
- status conductor is shorted to ground
- status conductor is cut
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Temperature Controlled
Fan
The temperature controlled
fan operates (to prevent overheating) when:
- LO on TC620H output pin indicates
over-temperature
- +5 V supply is lost
- control line is shorted to ground
- control line is broken
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High Current and Voltage Non-Inverting
Driver
Non-inverting driver
features unusually low rail-to-rail current loss in HI
state. |

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Electronic Circuit Breakers Offer Wide
Adjustment Range
At low currents, the QBAR® switch stays in its normally-closed state, It
snaps to open, breaking the circuit when I load is
too high for too long. Specifically when the voltage
across the breaker (VBR) applies sufficient voltage via
Rin for long enough to charge Cdelay to the QBAR® switch's input threshold voltage, the QBAR® switch snaps open. These circuit breakers can
be reset by cycling the power supply or shorting Cdelay.
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Slow-Start
Circuit
Frequently, full system
operations must be inhibited until all supplies are up
and other components are functioning properly. Slow-start
circuits can both prevent damage to fragile components
and help avoid a system's hanging-up in an unsatisfactory
state. |

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Motor
Dynamic Braking
QBAR® switches provide
motor dynamic braking when power is lost. On power
disconnect, and without the QBAR®
switches, a FET H-Switch will allow the motor to continue
spinning freely. |

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Off-Line
Not-Ready Indicator
QB312 series high voltage QBAR®
switches can provide indicators and other functions for
off-line applications in the US and Europe. Not-ready
indicator is ON while logic or other power supply ramps
up. |

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Battery
Systems
Unlike all other non-inverting switch ICs, QBAR®
switches require no connecting wire to the hot battery
lead, thus reducing the number of "hot" lead
connections and the consequent hazard from shorts to
ground. |

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