Safety /
Protection Circuits, Page 10
Safety / Protection: #-B
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Last Updated on:
Wednesday, November 29, 2017 05:39 AM |
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Links to electronic circuits, electronic schematics, designs for engineers,
hobbyists, students & inventors:
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Thermal Shutdown/ Protection - Add this circuit to either turn the
amp off or activate a cooling fan if it overheats … [Rod Elliott (ESP)] |
Thermal
switches provide circuit disconnect - 09/04/03 EDN Design Idea A single temperature sensor
can provide an interrupt to a microcontroller when the measured temperature goes out of range. You
need multiple temperature sensors when you have to monitorthan one hot spot. A microcontroller
implements… [by Mark Cherry, Maxim Integrated Products, Sunnyvale, CA] |
Three-Phase
Motor Driver Prevents Stall - 01/05/95 EDN Design Idea The circuit in Fig 1 drives a small
24V, 50-Hz motor at about 30 to 40 Hz for use as a chopper motor. The best starting speed for the
motor is about half the final running speed. Therefore, the circuit uses an intermediate speed … [by
PM Kirk[by, Crumpsall Electronics, Surrey, England] |
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Timer Reboots PC's -
06/05/97 EDN Design Idea When you use a PC to control a process or collect data, it's often desirable to have a
watchdog timer reboot the computer if it runs astray. The circuit in Figure 1 uses a PIC16C84.… [by Charles
Hamilton, Burr-Brown Corp, Tucson, AZ] |
Transistors offer thermal protection for controller - 07/19/01 EDN Design Idea When a switch-mode
power-supply controller, such as On Semiconductor's NCP1200, operates at a high ambient temperature, you should
protect the entire power supply against lethal thermal runaway. The NCP1200 operates directly from t… [by
Christopher Basso, On Semiconductor, Toulouse, France] |
Turn Your Old Inverter Into An Emergency
Power System - An inverter turned into emergency power system, which turns on when the mains supply fails,
and more importantly doesn’t turn on when the main supply is available … [© EFY Enterprises Pvt. Ltd. All rights
reserved.] |
Two buttons provide safe start -
07/06/00 EDN Design Idea The circuit in Figure 1 provides a safety interlock that checks the actuation of two
pushbuttons before enabling a relay. When you push both buttons, the circuit actuates the relay. At that point,
you can release one of the switc… [by Vincent Himpe, Alcatel Microelectronics, Desselgem, BelgiumVincent Himpe,
Alcatel Microelectronics, Desselgem, Belgium] |
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Undershoot Protection When using Bus Switches - Pericom
Semiconductor Application Note # 030… |
Use of Video Technology to Improve Automotive
Safety Becomes More Feasible with Blackfin Processors - Analog Devices-Analog Dialogue… [by Gentile,
Rick and Katz, David and Lukasiak, Tomasz] |
Voltage Monitor Prevents Deep
Discharge of Battery - 09/26/96 EDN Design Idea To avoid the deep discharge that can destroy or
shorten the life of a rechargeable battery, you must disconnect its load before the discharge is
complete. This disconnect function requires a battery-voltage monitor, which must incorporate
considerable hysteresis to prevent chatter in the disconnect switch. The chatter occurs as the battery
voltage first dips below threshold and then bounces back on load removal.… [by Ron Clark and Larry Suppan,
Maxim Integrated Products] |
Voltage Protection - Safety devices like fuses provide
protection against excess current, but do nothing for transients and short duration spikes of high
voltahe on the power supply lines.This circuit uses the "crowbar" method and provides fast protection
against transient voltage spikes… [Andy Collison] |
Watchdog circuit protects against loss of battery charger's control signals - 07/21/05 EDN Design
Idea Hardware circuit keeps software-based charging within limits… [by Andy Fewster, Maxim Integrated
Products Inc, Hampshire, UK] |
Watchdog circuit uses AC
triggering - 08/16/01 EDN Design Idea A dc-triggered reset of a watchdog circuit is prone to failure.
If the watchdog program hangs up, then the reset signal becomes activated continuously, and the
microprocessor has no way to escape the situation. We found that a simp… [by Shyam Tiwari, Sensors
Technology Private Ltd, Gwalior, India] |
Watchdog
Circuit uses Leftover Gates - 08/01/96 EDN Design Idea The reset and µP-controlled watchdog
circuit in Figure 1 a makes good use of some unused inverter gates in IC1. The design is extremely
simple. The circuit is a continuously running oscillator with programmable high- and low-leve… [by Shyam
Sunder Tiwari, IGCAR, Kalpakkam, India] |
Watch-Dog for Telephones - Most of the telephone
security devices available in market are simple but quite expensive. These devices provide blinking or
beeping type line-tap/misuse indications. Quite often they do not offer guaranteed protection against
unauthor-ised operation. A very simple and uni- que circuit of a telephone watch-dog to safeguard
subscriber telephone lines against any fraud is described here.This little circuit keeps continuous watch
over the telephone lines and sounds an alarm in case of any misuse. In addition it transmits a loud tone
through the telephone lines to prevent further misuse.… |
Watchdog reset catcher aids embedded system
debugging - 11/19/98 EDN Design Idea (Multiple circuits included.Scroll to find this one)A simple
"junk-box" circuit uses a 4013CMOS flip-flop and a handful of passive components to determine whether
random resets are the result of a blown stack or the result … [by Scott Newell, PCSI, Fort Smith, AR] |
Watchdog
Time-Out Is Independent of Reset - 09/01/95 EDN Design Idea Many embedded systems use µP
supervisors with on-chip watchdog timers. Some supervisors, such as the MAX691, allow you to select
different watchdog and reset time-out periods, depending on how you connect pin 7 (Osc In] and pin 8 (…
[by Larry Buyan, Criticare Systems Inc, Waukesha, WI] |
Watchdog timer
allows entry to test mode - 07/19/01 EDN Design Idea Manuals for microprocessor-based devices
often include instructions for entering a "secret mode" in which you can test or reset the device. These
instructions typically ask you to depress and hold one or two switches for a minimum … [by Greg Sutterlin
and Larry Barnes, Maxim Integrated Products, Sunnyvale, CA, and Craig Gestler, Mining Safety Appliances
Co, Mars, PA] |
Watchdog Timer Assumes Varied Roles - The following application
note demonstrates alternative uses for the MAX6369-MAX6374 family of pinselectable watchdog timers.
Alternative uses include a power saving power-on LED indicator circuit, load connect/disconnect circuit
and push-button reset circuit. (Maxim APPLICATION NOTE 582) … |
Watchdog timer assumes
varied roles - 02/01/01 EDN Design Idea The MAX6369-74 series of pin-selectable watchdog timers
are designed to superviseµP activity and indicate when a system is working improperly. During normal
operation, aµP should repeatedly toggle the WDI (watchdog input) before the selected watchdog-time… [by
Terry Millward, Maxim Integrated Products, Lambourn Hungerford, UK ] |
Watchdog Timer Reboots
PC's - 06/05/97 EDN Design Idea When you use a PC to control a process or collect data, it's often
desirable to have a watchdog timer reboot the computer if it runs astray. The circuit in Figure 1 uses a
PIC16C84.… [by Charles Hamilton, Burr-Brown Corp, Tucson, AZ] |
Watchdog-reset catcher aids
embedded-system debugging - 11/19/98 EDN Design Idea (File has serval designs) Power op amps have
a real need for active output-current limiting. Most power-amplifier designs rely on the voltage drop
across a user-supplied sense resistor to turn on an internal transistor. This method has several
drawbacks, notably, an inability to change the current-limit point under program control. The
current-limit circuit in Figure 1 allows you to establish the setpoint by applying a voltage to one of
the amplifier's pins. With this design, it is possible to set the current-limit point with the output of
a DAC, possibly under the control of an embedded µC.… [by Joe Engle, Burr-Brown Corp, Tucson, AZ] |
What is a Thyristor Surge Protector Device - MicroNote 105 from
Microsem Reviews the basics of an avalanche voltage triggered thyristor designed for transient voltage
protection, used largely for telecom signal lines… |
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