P rotection circuits for critical devices in regulator circuits

Linear IC regulators contain integrated security circuits which will make them virtually immune to harm from either extortionate load current or temperature that is running is high. The 2 security circuits contained in nearly all IC that is linear are:

1) Thermal Shutdown

2) Current Limiting

The thermal shutdown, current limiter, and voltage error amplifier make up three distinct and separate control loops that have a definite hierarchy (pecking order)which allows one to "override" the other. The order of command (and importance) of the loops is:

1) Thermal Limit (IC is regulating junction temperature/power dissipation)

2) Current Limit (IC is regulating load current)

3) Voltage Control (IC is regulating output voltage)

This hierarchy ensures that a linear regulator will in most cases you will need to run in "constant voltage" mode, where in actuality the voltage mistake amplifier is managing the production voltage up to and including value that is fixed. But, this assumes that both force that is effective and junction temperature are below their limitation limitation values. The restricting that is existing will need control and force force present towards the set restricting value (overriding the voltage blunder amplifier) in the event that load increases which can be current your restricting value. The voltage blunder amplifier can resume control only when the load up-to-date is paid down adequately to effect a result of the restricting that exists to discharge control. This might be covered much more information in the "Current Limiting" area. An improvement in die temperature (no matter cause) approaching the limitation restriction (about 160°C) can result in the shutdown that is cut that is thermal towards the power transistor, ergo reducing load present and power dissipation that is interior. Take into account that the limiter that is thermal override both the limitation that is current because the voltage error amplifier.Thermal shutdown is detailed into the component that is next. It's important to understand that a regulator holds its production voltage fixed only one time it truly is in constant voltage mode. The manufacturing voltage are going to be reduced as needed to keep carefully the strain present during the set value that is limiting restricting that occurs. The production voltage falls along side load up-to-date may virtually virtually be paid down to any value (including zero) in thermal limiting. No performance specs being characteristic when a component is operating in thermal shutdown mode