Outdoor Digital Signage,Outdoor Digital Advertising Boards,Outdoor Digital Signs,Digital Sign Board Outdoor Shanghai Really Technology Co.,Ltd , https://www.really-led.com
Ltc3789 chip Chinese information and recommended parameters
The LTC3789 is a high-performance buck-boost switching regulator controller designed to operate with input voltages that can be higher, lower, or equal to the output voltage. It features a constant-frequency, current-mode architecture that allows for phase-lockable operation up to 600kHz. This makes it ideal for applications requiring stable and efficient power conversion across varying input conditions. The device also includes an output current feedback loop, making it well-suited for battery charging systems.
With a wide input and output range of 4V to 38V (with a maximum of 40V), the LTC3789 supports seamless and low-noise conversion between different voltage levels. Its versatility makes it a popular choice in automotive, telecommunications, and battery-powered systems where reliable power management is essential.
In both buck and boost modes, the LTC3789 uses a proprietary current-mode control architecture to ensure consistent frequency operation, supported by four powerful N-channel MOSFET gate drivers. The controller provides accurate constant current regulation over a wide input voltage range, ensuring stable performance even under fluctuating conditions. Additionally, it includes input and output current limit features to prevent overload and protect connected devices.
The LTC3789 offers comprehensive fault protection against overvoltage, overcurrent, and short-circuit conditions, ensuring safe operation in all modes. During shutdown, it disconnects both the input and output voltages to minimize power consumption. Users can choose between continuous or pulse skip mode to optimize efficiency, especially at light loads. Pulse skip mode minimizes ripple, while forced continuous mode maintains a constant frequency for noise-sensitive applications.
The device also includes an adjustable soft-start function, a power-good output signal, and ±1.5% reference accuracy over a wide temperature range from -40°C to 125°C, ensuring reliable performance in harsh environments.
When the output voltage reaches within 10% of its set point, the power-good pin generates a signal, indicating that the system is operating correctly. The LTC3789 is available in two compact packages: a low-profile 28-pin 4mm x 5mm QFN and a narrow-body SSOP package, making it suitable for space-constrained designs.
**LTC3789 Pin Description**
The LTC3789 has 28 pins, each serving a specific function critical to its operation:
1. **VFB (PIN1/PIN26)** – Feedback pin for the error amplifier.
2. **SS (PIN2/PIN27)** – Soft start input; used to control the rise time of the output voltage.
3. **SENSE+ (PIN3/PIN28)** – Non-inverting input of the current sense comparator.
4. **SENSE- (PIN4/PIN1)** – Inverting input of the current sense comparator.
5. **ITH (PIN5/PIN2)** – Error amplifier output and switching regulator compensation point.
6. **SGND (PIN6/PINS3, EXPOSED PAD PIN29)** – Small signal ground; must be connected to the negative terminal of the input filter capacitor.
7. **MODE/PLLIN (PIN7/PIN4)** – Mode selection or external synchronization input.
8. **FREQ (PIN8/PIN5)** – Frequency setting pin; controls the internal oscillator frequency.
9. **RUN (PIN9/PIN6)** – Run control pin; turns the controller on or off.
10. **VINSNS (PIN10/PIN7)** – VIN sense input pin for buck-boost conversion.
11. **VOUTSNS (PIN11/PIN8)** – VOUT sense input pin for buck-boost conversion.
12. **ILIM (PIN12/PIN9)** – Input/output average current detection threshold setting.
13. **IOSENSE+ (PIN13/PIN10)** – Non-inverting input of the average current sense amplifier.
14. **IOSENSE- (PIN14/PIN11)** – Inverting input of the average current sense amplifier.
15. **TRIM (PIN15/PIN12)** – Must be connected to GND; should not float.
16. **EXTVCC (PIN20/PIN17)** – External power input; powers the internal LDO.
17. **INTVCC (PIN21/PIN18)** – Output of the internal LDO; powers the control circuitry.
18. **VIN (PIN22/PIN19)** – Main power input pin.
19. **BG1, BG2 (PINS 23, 19/PINS 20, 16)** – High-current gate drivers for the bottom MOSFET.
20. **PGND (PIN24/PIN21)** – Drive power ground; connects to COUT, CIN, and RSENSE.
21. **BOOST1, BOOST2 (PINS 25, 18/PINS 22, 15)** – Bootstrap power supply for top MOSFET gates.
22. **TG1, TG2 (PIN 26, 17/PIN 23, 14)** – Gate drivers for the top MOSFETs.
23. **SW1, SW2 (PINS 27, 16/PINS 24, 13)** – Switching nodes connected to the inductor.
24. **PGOOD (PIN 28/PIN 25)** – Power good output; indicates when the output is stable.
**Internal Equivalent Circuit of LTC3789**
The LTC3789 operates as a current-mode controller, using a proprietary topology to regulate output voltage regardless of input conditions. It employs a current sense resistor to monitor inductor current, which is controlled by the voltage on the ITH pin—output of the error amplifier. The VFB pin receives the feedback voltage, which is compared to an internal reference. This allows for precise regulation of the output voltage through either feedback or current sensing.
**LTC3789 Performance Summary**
- Single inductor architecture
- Supports input voltages higher, lower, or equal to output
- Input range: 4V to 38V (max 40V)
- Output range: 0.8V to 38V
- Programmable input or output current limit
- Synchronous rectification
- Up to 98% efficiency
- Integrated MOSFET gate drivers
- Can deliver up to 150W output power
- Output disconnection during shutdown
- PLL-controlled frequency from 200kHz to 600kHz
- Power good output signal
- ±1.5% reference accuracy over -40°C to +125°C
- Fast transient response with easy loop compensation
- Overvoltage and overcurrent protection
- 5.5V internal and external VCC LDO
**Typical Application**
The LTC3789 is commonly used in various power supply configurations, including but not limited to battery chargers, DC-DC converters, and industrial power supplies. Its flexible design and robust features make it a reliable solution for engineers looking for efficient and stable power management in diverse environments.