Overview
The UCC28084DRG4 is a member of the UCC2808x family of BiCMOS pulse width modulation (PWM) controllers designed by Texas Instruments. These controllers are specifically tailored for dc-to-dc or off-line fixed-frequency current-mode switching power supplies. The UCC28084DRG4 is configured for push-pull topology and features dual output stages that switch at half the oscillator frequency, ensuring efficient and reliable operation.
Key Specifications
| Parameter | Min | Typ | Max | Units |
|---|---|---|---|---|
| Start-up Current | 120 | 200 | - | µA |
| Supply Current (CTRL = 0 V, CS = 0 V) | 1.5 | 2.5 | - | mA |
| Undervoltage Lockout Start Threshold Voltage | 4.1 | 4.3 | 4.5 | V |
| Minimum Operating Voltage after Start | 3.9 | 4.1 | 4.3 | V |
| Oscillator Frequency (2 x f(OUTA)) | 180 | 200 | 220 | kHz |
| Output Current (OUTA, peak) | -0.5 | - | - | A |
| Output Current (OUTB, peak) | 1.0 | - | - | A |
| Maximum Duty Cycle | 48% | 49% | 50% | % |
| Soft-Start Interval Time | 1.3 | 3.5 | 8.5 | ms |
| Operating Temperature Range | -40 | - | 85 | °C |
| Package Type | 8-SOIC | - | - | - |
Key Features
- Programmable Slope Compensation: Allows for adjustable slope compensation to improve stability in current-mode control.
- Internal Soft-Start: The UCC28084 features a built-in soft-start mechanism that gradually increases the output duty cycle to prevent inrush currents.
- Cycle-by-Cycle Current Limiting: Ensures protection against overcurrent conditions by limiting the peak current on a cycle-by-cycle basis.
- Low Start-Up Current: Typical start-up current of 120 µA and run current of 1.5 mA, making it energy-efficient.
- Single External Component Oscillator: Programmable from 50 kHz to 1 MHz, allowing for flexible frequency settings.
- High-Current Totem-Pole Dual Output Stage: Drives push-pull configuration with 1-A sink and 0.5-A source capability.
- Current Sense Discharge Transistor: Improves dynamic response by discharging the filter capacitor on the CS pin during each cycle.
- Internally Trimmed Bandgap Reference: Provides a stable voltage reference.
- Undervoltage Lockout with Hysteresis: Protects the device from operating below the minimum voltage threshold.
Applications
- High-Efficiency Switch-Mode Power Supplies: Ideal for designing efficient power supplies with reduced energy losses.
- Telecom dc-to-dc Converters: Suitable for telecommunications equipment requiring reliable and efficient power conversion.
- Point-of-Load or Point-of-Use Power Modules: Used in modular power systems where compact and efficient power conversion is necessary.
- Low-Cost Push-Pull and Half-Bridge Applications: Applicable in various power conversion topologies where cost and efficiency are critical.
Q & A
- What is the primary function of the UCC28084DRG4? The UCC28084DRG4 is a PWM controller designed for dc-to-dc or off-line fixed-frequency current-mode switching power supplies.
- What is the typical start-up current of the UCC28084DRG4? The typical start-up current is 120 µA.
- What is the range of the programmable oscillator frequency? The oscillator frequency can be programmed from 50 kHz to 1 MHz.
- What is the maximum output current capability of the OUTB pin? The OUTB pin can sink up to 1 A.
- Does the UCC28084DRG4 have internal soft-start? Yes, the UCC28084DRG4 features a built-in soft-start mechanism.
- What is the purpose of the current sense discharge transistor? The current sense discharge transistor improves dynamic response by discharging the filter capacitor on the CS pin during each cycle.
- What are the typical undervoltage lockout start and stop thresholds for the UCC28084DRG4? The start threshold is typically 4.3 V, and the stop threshold is typically 4.1 V.
- What is the operating temperature range of the UCC28084DRG4? The operating temperature range is from -40°C to 85°C.
- In what package types is the UCC28084DRG4 available? It is available in 8-SOIC, 8-PDIP, and 8-TSSOP packages.
- What is the maximum duty cycle of the UCC28084DRG4? The maximum duty cycle is 50%.
