Overview
The UCC28083DRG4 is part of the UCC38083/4/5/6 family of BiCMOS pulse width modulation (PWM) controllers designed by Texas Instruments. These controllers are tailored for dc-to-dc or off-line fixed-frequency current-mode switching power supplies. The UCC28083DRG4 is specifically configured for push-pull topology, with dual output stages that switch at half the oscillator frequency using a toggle flip-flop. This architecture ensures efficient and reliable operation in various power supply applications.
Key Specifications
| Parameter | Minimum | Typical | Maximum | 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 (UCC38083/5) | 11.5 | 12.5 | 13.5 | V |
| Undervoltage Lockout Start Threshold Voltage (UCC38084/6) | 4.1 | 4.3 | 4.5 | V |
| Oscillator Frequency (2 x f(OUTA)) | 180 | 200 | 220 | kHz |
| Maximum Duty Cycle (OUTA or OUTB) | 48% | 49% | 50% | % |
| Output Rise Time (CLOAD = 1 nF) | 25 | - | 60 | ns |
| Output Fall Time (CLOAD = 1 nF) | 25 | - | 60 | ns |
| Soft-Start Interval Time (UCC38083/4) | 1.3 | 3.5 | 8.5 | ms |
| Soft-Start Interval Time (UCC38085/6) | 30 | 75 | 110 | µs |
Key Features
- Programmable Slope Compensation: Allows for adjustable slope compensation to enhance stability in current-mode control.
- Internal Soft-Start: The UCC38083 and UCC38084 devices feature a built-in soft-start mechanism to gradually increase the output duty cycle, reducing inrush currents and stress on components.
- Cycle-by-Cycle Current Limiting: Provides overcurrent protection by limiting the peak current on a cycle-by-cycle basis.
- Low Start-Up Current: Starts up with a low current of 120 µA and runs at a typical current of 1.5 mA.
- Single External Component Oscillator: The oscillator frequency can be programmed from 50 kHz to 1 MHz using a single external resistor.
- High-Current Totem-Pole Dual Output Stage: Drives push-pull configurations with 1-A sink and 0.5-A source capability.
- Current Sense Discharge Transistor: Improves dynamic response by discharging the current-sense filter capacitor at each clock cycle.
- Internally Trimmed Bandgap Reference: Ensures stable voltage reference for accurate control.
- Undervoltage Lockout with Hysteresis: Protects the device from operating below the minimum voltage threshold, with hysteresis to prevent oscillations.
Applications
- High-Efficiency Switch-Mode Power Supplies: Ideal for designing efficient power supplies with minimal 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 distributed power systems where localized power conversion is necessary.
- Low-Cost Push-Pull and Half-Bridge Applications: Cost-effective solution for push-pull and half-bridge power supply configurations.
Q & A
- What is the typical start-up current of the UCC28083DRG4?
The typical start-up current is 120 µA.
- What is the range of the oscillator frequency that can be programmed?
The oscillator frequency can be programmed from 50 kHz to 1 MHz.
- What is the maximum duty cycle of the output stages?
The maximum duty cycle is less than 50%.
- Does the UCC28083DRG4 have an internal soft-start feature?
Yes, the UCC38083 and UCC38084 devices have an internal soft-start feature.
- What is the purpose of the current sense discharge transistor?
The current sense discharge transistor improves dynamic response by discharging the current-sense filter capacitor at each clock cycle.
- What are the typical output rise and fall times?
The typical output rise and fall times are 25 ns to 60 ns.
- What are the undervoltage lockout thresholds for the UCC38083/5 devices?
The turn-on/off thresholds are 12.5 V / 8.3 V.
- What are the undervoltage lockout thresholds for the UCC38084/6 devices?
The turn-on/off thresholds are 4.3 V / 4.1 V.
- In what packages is the UCC28083DRG4 available?
The device is available in 8-pin TSSOP (PW), 8-pin SOIC (D), and 8-pin PDIP (P) packages.
- What is the operating temperature range for the UCC2808x series?
The operating temperature range is −40°C to 85°C for the UCC2808x series.
