ОСОБЕННОСТИ

4-Switch Single Inductor Architecture Allows VIN

Above, Below or Equal to VOUT

Synchronous Switching: Up to 98% Efficiency

Proprietary Peak-Buck Peak-Boost Current Mode

Wide VIN Range: 4V to 60V

±1.5% Output Voltage Accuracy: 1V ≤ VOUT ≤ 60V

±3% Input or Output Current Accuracy with Monitor

Spread Spectrum Frequency Modulation for Low EMI

High Side PMOS Load Switch Driver

Integrated Bootstrap Diodes

No Top MOSFET Refresh Noise in Buck or Boost

Adjustable and Synchronizable: 150kHz to 650kHz

VOUT Disconnected from VIN During Shutdown

Available in 28-Lead TSSOP with Exposed Pad and

28-Lead QFN (4mm × 5mm)

AEC-Q100 Qualified for Automotive Applications

 

ПРИЛОЖЕНИЯ

Automotive, Industrial, Telecom Systems

High Power Battery-Powered System

 

ОПИСАНИЕ

The LT8390 is a synchronous 4-switch buck-boost DC/DC controller that regulates output voltage, input or output current from an input voltage above, below, or equal to the output voltage. The proprietary peak-buck/peak-boost current mode control scheme allows adjustable and synchronizable 150kHz to 650kHz fixed frequency operation, or internal ±15% triangle spread spectrum frequency modulation for low EMI. With a 4V to 60V input voltage range, 0V to 60V output voltage capability, and seamless low noise transitions between operation regions, the LT8390 is ideal for voltage regulator, battery and supercapacitor charger applications in automotive, industrial, telecom, and even battery-powered systems.

The LT8390 provides input or output current monitor and power good flag. Fault protection is also provided to detect output short-circuit condition, during which the LT8390 retries, latches off, or keeps running.

The LT8390 is a current mode DC/DC controller that can regulate output voltage, input or output current from input voltage above, below, or equal to the output voltage. The ADI proprietary peak-buck peak-boost current mode control scheme uses a single inductor current sense resistor and provides smooth transition between buck region, buck-boost region, and boost region.

 

Internal Charge Path

The LT8390 is a fixed frequency current mode controller.Each of the two top MOSFET drivers is biased from its floating bootstrap capacitor, which is normally re-charged by INTVCC through the integrated bootstrap diode D1 or D2 when the top MOSFET is turned off. When the LT8390operates exclusively in the buck or boost regions, one of the top MOSFETs is constantly on. An internal charge path, from VOUT and BST2 to BST1 or from VIN and BST1 to BST2, charges the bootstrap capacitor to 4.6V so that the top MOSFET can be kept on.

 

Shutdown and Power-On-Reset

The LT8390 enters shutdown mode and drains less than 2µA quiescent current when the EN/UVLO pin is below its shutdown threshold (0.3V minimum). Once the EN/UVLO pin is above its shutdown threshold (1V maximum), the LT8390 wakes up startup circuitry, generates bandgap reference, and powers up the internal INTVCC LDO. The INTVCC LDO supplies the internal control circuitry and gate drivers. Now the LT8390 enters undervoltage lockout (UVLO) mode with a hysteresis current (2.5µA typical) pulled into the EN/UVLO pin. When the INTVCC pin is charged above its rising UVLO threshold (3.78V typical), the EN/UVLO pin passes its rising enable threshold (1.233V typical), and the junction temperature is less than its thermal shutdown (165°C typical), the LT8390 enters enable mode, in which the EN/UVLO hysteresis current is turned off and the voltage reference VREF is being charged up from ground. From the time of entering enable mode to the time of VREF passing its rising UVLO threshold (1.89Vtypical), the LT8390 is going through a power-on-reset (POR), waking up the entire internal control circuitry and settling to the right initial conditions. After the POR, the LT8390 is ready and waiting for the signals on the CTRL and LOADEN pins to start switching.For more information, please refer to the data sheet.