Overview
The UC2844J, produced by Texas Instruments, is a single-ended current-mode Pulse Width Modulation (PWM) controller. This device is part of the UCx84x family, which is optimized for off-line and DC-to-DC converters. The UC2844J is designed to implement fixed-frequency current-mode control schemes with a minimal number of external components. It features an internally implemented undervoltage lockout (UVLO) with a low start-up current of less than 1mA, a precision reference trimmed for accuracy, and a totem-pole output stage capable of sourcing or sinking high-peak current. This controller is suitable for a variety of power supply applications, including switch-mode power supplies (SMPS) and DC-DC converters.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Operating Temperature Range | -40 | 85 | °C | |
| Start-up Current | < 1 | mA | ||
| UVLO Start Threshold | 7.8 | 8.4 | 9 | V |
| UVLO Minimum Operation Voltage after Turnon | 7 | 7.6 | 8.2 | V |
| Maximum Duty Cycle | 92 | 96 | 100 | % |
| Output Frequency | Up to 500 | kHz | ||
| Output Low Level (ISINK = 20 mA) | 0.1 | 0.4 | V | |
| Output High Level (ISOURCE = 20 mA) | 13 | 13.5 | V |
Key Features
- Optimized for off-line and DC-to-DC converters
- Low start-up current (< 1mA)
- Automatic feedforward compensation
- Pulse-by-pulse current limiting
- Enhanced load-response characteristics
- Undervoltage lockout with hysteresis
- Double-pulse suppression
- High-current totem-pole output
- Internally trimmed bandgap reference
- Up to 500kHz operation
- Error amplifier with low output resistance
Applications
- Switch-mode power supplies (SMPS)
- DC-DC converters
- Power modules
- Industrial power supplies
- Battery-operated power supplies
Q & A
- What is the operating temperature range of the UC2844J?
The UC2844J operates within a temperature range of -40°C to 85°C.
- What is the start-up current of the UC2844J?
The start-up current of the UC2844J is less than 1mA.
- What is the maximum duty cycle of the UC2844J?
The maximum duty cycle of the UC2844J is up to 100%.
- What is the output frequency range of the UC2844J?
The UC2844J can operate up to 500kHz.
- Does the UC2844J have undervoltage lockout (UVLO) with hysteresis?
Yes, the UC2844J features undervoltage lockout with hysteresis.
- What type of output stage does the UC2844J have?
The UC2844J has a high-current totem-pole output stage.
- Is the UC2844J suitable for DC-DC converters?
Yes, the UC2844J is optimized for DC-DC converters among other applications.
- Does the UC2844J support pulse-by-pulse current limiting?
Yes, the UC2844J supports pulse-by-pulse current limiting.
- What is the typical output low level voltage of the UC2844J when ISINK is 20 mA?
The typical output low level voltage is between 0.1 V and 0.4 V when ISINK is 20 mA.
- What is the typical output high level voltage of the UC2844J when ISOURCE is 20 mA?
The typical output high level voltage is between 13 V and 13.5 V when ISOURCE is 20 mA.
