Current-Mode PWM Controller The TL3845 is a high-performance current-mode PWM controller manufactured by Texas Instruments (TI). Below are its key specifications, descriptions, and features:
### **Specifications:**
- **Input Voltage Range (VCC):** 8V to 30V (operating), up to 36V (absolute max)
- **Oscillator Frequency Range:** Adjustable up to 500kHz
- **Output Duty Cycle Range:** 0% to <100%
- **Peak Output Current (Source/Sink):** ±1A
- **Reference Voltage (VREF):** 5V ±1%
- **Error Amplifier Gain Bandwidth:** 1MHz (typical)
- **Operating Temperature Range:** -40°C to +85°C (industrial)
- **Package Options:** 8-Pin PDIP, SOIC
### **Descriptions:**
- The TL3845 is a fixed-frequency current-mode PWM controller optimized for DC-DC converter and power supply applications.
- It features a trimmed oscillator for precise duty cycle control, a high-gain error amplifier, and a current-sensing comparator for cycle-by-cycle current limiting.
- The device includes an undervoltage lockout (UVLO) function to ensure proper startup and shutdown behavior.
### **Features:**
- **Current-Mode Control:** Improves loop response and simplifies compensation.
- **Adjustable Frequency:** Set via external resistor and capacitor.
- **Undervoltage Lockout (UVLO):** Ensures reliable operation under low input voltage conditions.
- **Soft-Start Capability:** Reduces inrush current during startup.
- **Pulse-by-Pulse Current Limiting:** Enhances system protection.
- **Totem-Pole Output:** Supports MOSFET or bipolar transistor drivers.
- **Low Startup Current:** Typically 0.5mA.
The TL3845 is commonly used in offline and DC-DC power supplies, battery chargers, and industrial power systems.
(Source: Texas Instruments datasheet for TL3845.)
