Overview
The UC2843BN is a high-performance current mode PWM (Pulse Width Modulation) controller from STMicroelectronics. This IC is part of the UC284xB family, designed to implement off-line or DC to DC fixed frequency current mode control schemes with a minimal external parts count. It features a trimmed oscillator for precise frequency control, automatic feed-forward compensation, and latching PWM for cycle-by-cycle current limiting. The device is suitable for driving N-Channel MOSFETs and includes an internally trimmed reference with under-voltage lockout and high current totem pole output stage.
Key Specifications
| Parameter | Symbol | Min | Typ | Max | Unit |
|---|---|---|---|---|---|
| Supply Voltage | Vi | - | - | 30 | V |
| Output Current | IO | - | - | ±1 A | A |
| Output Energy (Capacitive Load) | EO | - | - | 5 µJ | µJ |
| Reference Output Voltage | VREF | 4.95 | 5.00 | 5.05 | V |
| Oscillator Frequency | fOSC | 48 | 50 | 52 | kHz |
| Under-Voltage Lockout Start Threshold | - | 7.8 | 8.4 | 9.0 | V |
| Maximum Duty Cycle | - | 94 | 96 | 100 | % |
| Operating Junction Temperature | TJ | -40 | - | 150 | °C |
| Storage Temperature Range | Tstg | -65 | - | 150 | °C |
Key Features
- Trimmed oscillator for precise frequency control up to 500 kHz.
- Current mode operation with automatic feed-forward compensation.
- Latching PWM for cycle-by-cycle current limiting.
- Internally trimmed reference with under-voltage lockout and hysteresis.
- High current totem pole output stage suitable for driving N-Channel MOSFETs.
- Low start-up and operating current (less than 0.5 mA start-up current).
- Precision error amplifier output available for loop compensation.
- External clock synchronization capability.
Applications
The UC2843BN is ideal for various power management applications, including:
- Off-line power supplies.
- DC to DC converters.
- Switch-mode power supplies.
- High-frequency power conversion systems.
- Industrial power supplies and motor control systems.
Q & A
- What is the primary function of the UC2843BN?
The UC2843BN is a high-performance current mode PWM controller designed for implementing off-line or DC to DC fixed frequency current mode control schemes.
- What is the typical oscillator frequency of the UC2843BN?
The typical oscillator frequency is around 50 kHz, but it can range from 48 kHz to 52 kHz depending on the configuration.
- What is the maximum duty cycle for the UC2843BN?
The maximum duty cycle for the UC2843BN is up to 100%.
- What is the under-voltage lockout start threshold for the UC2843BN?
The under-voltage lockout start threshold is between 7.8 V and 9.0 V.
- What is the maximum output current of the UC2843BN?
The maximum output current is ±1 A.
- Can the UC2843BN be synchronized with an external clock?
- What is the operating junction temperature range for the UC2843BN?
The operating junction temperature range is from -40°C to 150°C.
- What is the storage temperature range for the UC2843BN?
The storage temperature range is from -65°C to 150°C.
- What type of output stage does the UC2843BN have?
The UC2843BN has a high current totem pole output stage suitable for driving N-Channel MOSFETs.
- What is the typical start-up current of the UC2843BN?
The typical start-up current is less than 0.5 mA.
