1. What is a Reset IC?
A Reset IC (a voltage detector or power supply monitoring IC) is a power supply IC.
A reset IC is used mainly for monitoring the power supply voltage of electronic devices to monitor and detect whether the voltage drops below a threshold or exceeds a certain level.
Reset ICs can be found in many familiar devices around us. They work silently in the background “to monitor the power supply voltage” ensuring that smart phones, PCs, car navigation systems and a wide variety of other electronic devices start up and stop safely.
While other components (for example, microcontrollers*) can take over some reset IC functions, there are functions and safety aspects that are best handled by a reset IC. In the following, we will further elaborate on reset IC capabilities.
2. A Reset IC can
Ensure the safe startup of a microcontroller
Many electronic devices incorporate a microcontroller (MCU)*, a semiconductor that operates as a brain controlling electronic device operations.
An MCU requires a certain minimum operation voltage. If the MCU is started up at a voltage below this voltage or the power supply voltage is unstable, the MCU might malfunction or the devices it controls could malfunction or fail.
To ensure safe MCU operation, a Power On Reset* operation must be performed.
If the power supply is unstable at startup, the power on reset generator in the MCU may not function and operation after startup will be unstable.
To prevent this from occurring, a reset IC monitors the output voltage of the power supply IC to detect when it exceeds MCU operation voltage. When it does, the reset IC clears the reset signal to allow the MCU to start up. By setting a delay time, the MCU reset status can be maintained to allow enough time for an MCU power on reset.
*Microcontroller(MCU)…A processor for controlling electronic devices. A microcontroller operates according to input signals as the brain of electronic devices.
*Power On Reset…Operation initializing registers in the MCU at startup.
Extend battery life
As battery capacity approaches zero, the drop in output voltage accelerates.
This makes it essential to control the operation of battery operated devices before output voltage depletion starts to accelerate to prevent device malfunction and failure.
By having a reset IC monitor battery output voltage, a reset signal is output to control device operation before battery voltage depletion starts to accelerate. In addition, a reset IC with high-accuracy detection voltage will further help extend battery life.
Automotive devices also need monitoring of battery voltage.
From a safety aspect, automotive devices require a stand-alone voltage monitoring mechanism, in which case use of high-withstand voltage automotive ICs is ideal.
The ultimate reset IC for battery-operated devices
High-accuracy of ±0.5%
Detection voltage from 0.8V
Add redundancy to the MCU
Sometimes MCUs with an integrated reset function have to be combined with a reset IC.
For example, in automotive devices, industrial equipment and other devices requiring a high degree of safety, voltage monitoring relying only on an MCU may not always be enough.
To prevent the unlikely event that an MCU defect prevents normal operation of power supply monitoring, a reset IC can be added as a fail-safe measure to enable the configuration of a system with high redundancy.
Monitor for voltage rises (= overvoltage)
Reset ICs are also used to monitor for voltage rises (= overvoltage).
Overvoltage detection is mainly an automotive device requirement.
An overvoltage detection function can detect if the power voltage from the battery for some reason should rise and can prevent malfunction and failure of the system core (MCU, etc.) before they occur.
The A/D converter (ADC) of an MCU is a simple measure to monitor for overvoltage, but in automobiles where safety is essential, a stand-alone voltage detection function independent of the MCU is often required.
Although there are various methods to meet such requirements by having a composite IC,etc. with an overvoltage detection function and by configuring a detection circuit using a comparator or other device, a reset IC is one of the most effective methods.
A reset IC can be set up as shown in the block diagram below to configure an MCU independent mechanism for monitoring voltage drops and rises. This circuit configuration is simpler than one involving a comparator.
And, use of a reset IC capable of high-accuracy voltage rise detection will enable even safer overvoltage detection.
3. ABLIC’s ICs
As the leading reset IC company, ABLIC has a 35-year manufacture and development track record with a share of the market that is second to none in the industry.
(*According to ABLIC market data)
If you are looking for a reset IC, ABLIC’s ICs come highly recommended.