TL3843BDRG4

Due to market price fluctuations, if you need to purchase or consult the price. You can contact us or emial to us:   sales@allicdata.com

PMIC - Voltage Regulators - DC DC Switching Controllers

The TL3843BDRG4 is a BiCDMOS integrated circuit (IC) designed foruse as a controller in Switch Mode Voltage Regulator (SMVR)applications. When used in conjunction with a single power switchsuch as an n-channel MOSFET, an inductor and a few other passivedevices, it is capable of providing low noise, fast transientresponse and wide output voltage adjustment. The control schemeutilizes a topology that inherently minimizes differential inputvoltage and improves transient response.

Features

• Wide input voltage range from 4.0V to 24V
• Internal current limit with foldback
• High frequency oscillator (frequency programmable)
• Input overload latch and short-circuit protection
• Output over-voltage protection
• Undervoltage lockout with hysteresis
• Pulse-by-pulse current limit
• Integrated temperature monitor and thermal protection circuitry
• Pre-biased startup
• Soft-start option on startup and output overshoot prevention

Application fields

The TL3843BDRG4 can be used to regulate the output voltage in awide range of applications such as DC-DC converters, battery chargers,current regulators, lighting systems, notebook computerpower supplies, modems and telecommunication systems.

Working Principle

The operation of the TL3843BDRG4 depends on two main components -an oscillator and an error amplifier, both of which are controlled byan internal control loop. The oscillator circuit provides a sawtoothwaveform, which is used to periodically turn on and off a powerswitch such as an N-channel MOSFET. The error amplifier is used todetect any variations in the output voltage and it adjusts theoscillator frequency accordingly, thus maintaining the desired outputvoltage. The control loop also provides many important features suchas current limit, overload protection and under-voltage lock-out.

In order to understand its operation, it is useful to examine theTL3843BDRG4’s block diagram, shown below.

The oscillator circuit consists of two voltage-controlledoscillators (VCOs) connected in series, providing a sawtoothwaveform. The two VCOs can be independently controlled, allowingfor fine tuning of the switching frequency. The error amplifierprovides feedback to the VCOs and adjusts the oscillator frequencyaccordingly. The current limit circuit helps to protect thecontroller from overload and short-circuit conditions. Finally, theunder-voltage lockout (UVLO) circuit prevents the oscillator fromstarting if the input voltage is too low.

In normal operation, the TL3843BDRG4 controller oscillates at aconstant frequency, determined by the values of the components inthe oscillator circuit. The Error amplifier is used to compare theoutput voltage with a reference voltage and to adjust the dutycycle of the power switch accordingly. The error amplifier alsoprovides a feedback path to the current limit circuit, whichtriggers if the switch current exceeds a certain threshold. Whenthe current limit circuit triggers, it reduces the VCO frequencyand causes the duty cycle to reduce, thus limiting the switchcurrent.

Conclusion

The TL3843BDRG4 is an excellent choice for applicationsrequiring low noise, fast transient response and wide outputvoltage adjustment. It features a wide input voltage range,integrated current limit and protection circuits, as well as anintegrated temperature monitor with thermal protection. It can beused as a controller in a wide range of applications such as DC-DCconverters, battery chargers, current regulators, lighting systems,notebook computer power supplies, modems and telecommunicationsystems.

The specific data is subject to PDF, and the above content is for reference