Choice of protection in automotive applications:  AN554: length of the disturbance (130 ms : see  4.1, paragraph III.4) The minimum value of C will be : Cmin = (130 * 10-3 / Req)/ln (VCC min / Vbat) with Req = equivalent resistance of the electronic unit Req = VCC min... (Circuit / schematic design added 6/06)

Circuit breaker handles Voltages to 32V:  05/25/00 EDN-Design Ideas / (added 2/06) The simplicity of low-side current monitoring can mask the advantages of a high-side approach. You can monitor load currents in a power supply, a motor driver, or another power circuit on either the high or the low side (ground). However, don't let the ease of low-side monitoring cause you to overlook its dangers or the advantages of a high-side approach. Various fault conditions can bypass the low-side monitor, thereby subjecting the load to dangerous and undetected stresses. On the other hand, a high-side monitor connected directly to the power source can detect any downstream failure and trigger the appropriate corrective action. Traditionally, such monitors required a precision op amp, a boost power supply to accommodate the op amp's limited common-mode range, and a handful of precision resistors. Now, the MAX4172 IC can sense high-side currents in the presence of common-mode...

Circuit Breaker has Programmable Delay:  01/16/97 EDN-Design Ideas  The circuit in Figure 1 provides overload and short-circuit protection to a 5V power-supply output. The heart of the circuit is the LT1620, a charge-current controller designed for high-efficiency, switch-mode battery chargers. The IC's versatility allows you to use it as an electronic circuit breaker. The circuit amplifies the voltage across current-sense resistor R1 by a factor of 10 and averages it with capacitor C2. An error amplifier within the LT1620 compares the voltage on the AVG pin to the programming voltage on the PROG pin. Both amplifier inputs use VCC as a reference.  (08/05)

Circuit Detects and Disconnects OverVoltages:  04/25/96 EDN-Design Ideas / (Electronic Circuit diagram added 03/03)  

Circuit ensures safety in Power on operation:  04/24/03 EDN Design Ideas  /  (added 1/05)  Computers find universal use in industrial-control systems. During power- and start-up sequences (booting), the outputs of such control systems may yield uncontrolled pulses before the software defines the correct status. If these outputs control the power-on state of a system, these uncontrolled pulses could have dramatic consequences....

Circuit folds Back Current during fault conditions:  11/28/02 EDN Design Ideas  /  (added 1/05)  You can use monolithic linear regulators at currents lower than 5A for most applications. Most manufacturers of these devices integrate current-limiting and thermal shutdown to prevent damage during fault conditions. For currents greater than 5A, most linear supplies use controllers that allow the user to select the pass element to handle different current requirements....

Circuit Monitors Board, Air, and CPU Temperature to Protect System from Overheating:  App Note 941: Maxim IC  (Circuit / schematic design added 6/06)

Circuit offers series protection against power line transients:  10/14/04 EDN Design Ideas  / (added 5/05)  Voltage transients on low-voltage power lines can sometimes attain amplitudes many times the nominal voltage level. That behavior often calls for protection against the application of improper power levels. The usual way to protect sensitive circuitry against overvoltage is to add parallel clamps. Fuses or other current-limiting devices precede these clamps' high energy-absorption capability.

Circuit Prevents Deep Discharge of Batteries:  09/26/96 EDN-Design Ideas / (Electronic Circuit diagram added 03/03)   -- 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

Circuit Protects Against AC Line Disturbances:  07/29/98 EDN-Design Ideas / (Electronic Circuit diagram added 03/03)   -- operates by switching off the power supply upon detection of undervoltage or overvoltage conditions

Circuit protects battery from overdischarge:  04/12/01 EDN-Design Ideas / (added 11/05) / In some applications, it is undesirable to Overdischarge the battery, because it could irreversibly reduce the batterys capacity and the number of discharge/charge cycles. This circuit protects a single NiMH (nickel-metal-hydride) cell by disconnecting the load from the battery when it gets discharged enough.

Circuit protects Bus from 5V Swings:  11/14/02 EDN Design Ideas  /  (added 1/05)  The circuit in Figure 1 automatically detects voltage and protects a bus, such as a 3.3V-limited PCI bus, from 5V signal-level swings. You can also use the circuit to determine bus-voltage swings within one bus-cycle for setting appropriate termination voltages of protection diodes or termination resistors....

Circuit Protects Computer's Input:  05/26/94 EDN-Design Ideas  / (Electronic Circuit diagram added 03/03)   The circuit in Fig 1 performs input protection, level translation, isolation, and debouncing. The circuit allowed the output of a relay driver to connect to a computer even though the relay driver delivered a voltage as high as 24V and the relay driver had no ground connection. With the values in Fig 1 the low and high thresholds at the circuit's input were approximately 8 and 16V, respectively. The cutoff frequency was high enough to allow counting 1200 counts/min. The input withstood 110V ac continuously—the optoisolater's withstand voltage is 3 kV. I tested the debouncing function with a microswitch....    

Circuit protects system from overheating:  11/08/01 EDN Design Ideas  /  (added 1/05)  The two-chip circuit in Figure 1 provides fan control and overtemperature warning and shutdown signals to protect systems from excessive heat. The circuit monitors the temperature of the pc board and the die temperature of a CPU, an FPGA, or another IC with an on-chip temperature-sensing transistor. ...

Circuit Protects Systems from Overheating:  App Note 1126: Maxim IC  (Circuit / schematic design added 6/06)

Circuit Provides Flexible gain Ranges:  06/21/01 EDN-Design Ideas / (added 8/03)

Circuit provides reverse battery protection:  12/21/00 EDN-Design Ideas / (added 2/06) 

Circuit Safely Deep Discharges NiCd Battery:  04/29/99 EDN-Design Ideas / (added 2/06)  Nickel-cadmium (NiCd) batteries can possess an undesirable memory effect due to partial discharges. The remedy is a complete discharge before charging again. Figure 1a shows a simple circuit that performs this feat. Although relatively straightforward in concept, the circuit has three redeeming features: It receives its power from the battery undergoing the discharge; after the battery is fully discharged, the current drain is only approximately 4 µA, which is usually...

COP800 Based Automated Security/Monitoring System:  National Semiconductor - Application Note   (added 2/06)

Current limit protects power bus :  12/18/97 EDN-Design Ideas / (added 2/06)

Current Limiter Provides Latch up Signal:  01/01/98 EDN-Design Ideas / (Electronic Circuit diagram added 03/03)   -- Current-limiting circuit both signals a latch-up condition and prevents latch-up-induced overcurrent destruction of a CMOS IC or group of ICs

Data acquisition system uses fault protection:  04/15/04 EDN Design Ideas  /  (added 1/05)  Sensitive systems, such as those in aircraft, must withstand fault conditions, thereby avoiding component and system damage, because a sensor failure could cause a catastrophic event to occur. A channel protector, comprising two n-channel MOSFETs connected in series with a p-channel MOSFET, can protect sensitive components from voltage transients in the signal path, whether or not the power sup......

DC Fault Protection Circuit for Audio Amplifiers:  Circuit ideas how to replace traditional CD protection relays with MOSFETs (Electronic circuit added 5/02)

Dual comparator thermally protects lithium ion Battery:  09/18/03 EDN Design Ideas  /  (added 1/05)  Most manufacturers recommend that you don't change lithium-ion batteries at temperatures lower than 0°C or higher than 50°C. You can monitor both thresholds by adding a thermistor and dual (window) comparator to a lithium-ion battery charger (Figure 1). Set the low-temperature trip point at 2....