Overview
The L5991AD, produced by STMicroelectronics, is a primary controller IC designed for implementing offline or DC-DC power supply applications using fixed frequency current mode control. Developed in BCD60II technology, this device is optimized for high-performance power management. It features a range of advanced functionalities to ensure efficient, reliable, and safe operation of power supplies.
Key Specifications
| Parameter | Min. | Typ. | Max. | Unit |
|---|---|---|---|---|
| VCC Supply Voltage (ICC < 50mA) | - | - | 20 | V |
| Output Peak Pulse Current | - | - | 1.5 | A |
| VREF Output Voltage | 4.925 | 5.0 | 5.075 | V |
| Line Regulation (VCC = 12 to 20V) | 2.0 | - | 10 | mV |
| Load Regulation (IO = 1 to 10mA) | 2.0 | - | 10 | mV |
| Start-up Current Before Turn-on | 40 | 75 | 120 | µA |
| Operating Current (CT = 1nF, RT = 13.3kΩ, CO = 1nF) | 9 | 13 | - | mA |
| Quiescent Current (After turn on, CT = 1nF, RT = 13.3kΩ, CO = 0nF) | 7.0 | 10 | - | mA |
| Switching Frequency | - | - | 1 MHz | - |
| Output Low Voltage (IO = 250mA) | 1.0 | - | - | V |
| Output High Voltage (IO = 20mA, VCC = 12V) | 10 | - | 10.5 | V |
Key Features
- Current-mode control PWM with switching frequency up to 1 MHz
- Low start-up current (< 120 µA)
- High-current output drive suitable for power MOSFET (1 A)
- Fully latched PWM logic with double pulse suppression
- Programmable duty cycle (100% and 50% maximum duty cycle limit)
- Standby function with programmable oscillator frequency reduction
- Primary overcurrent fault detection with re-start delay
- PWM UVLO with hysteresis
- IN/OUT synchronization
- Latched disable
- Internal 100 ns leading edge blanking of current sense
- Programmable soft start
Applications
The L5991AD is designed for use in offline or DC-DC power supply applications, including:
- Switch-mode power supplies
- DC-DC converters
- Power management systems requiring high efficiency and reliability
- Industrial power supplies
- Consumer electronics power supplies
Q & A
- What is the maximum switching frequency of the L5991AD?
The maximum switching frequency of the L5991AD is up to 1 MHz.
- What is the start-up current of the L5991AD before turn-on?
The start-up current before turn-on is between 40 µA and 120 µA.
- What is the output peak pulse current capability of the L5991AD?
The output peak pulse current capability is up to 1.5 A.
- Does the L5991AD support programmable duty cycle?
Yes, the L5991AD supports programmable duty cycle with a maximum duty cycle limit of 100% and 50%.
- What is the purpose of the standby function in the L5991AD?
The standby function allows for oscillator frequency reduction when the converter is lightly loaded.
- Does the L5991AD have overcurrent protection?
Yes, the L5991AD features primary overcurrent fault detection with re-start delay.
- How does the L5991AD handle synchronization?
The L5991AD supports IN/OUT synchronization and can operate as both master and slave in synchronization modes.
- What is the quiescent current of the L5991AD after turn-on?
The quiescent current after turn-on is between 7.0 mA and 10 mA.
- What is the output low voltage of the L5991AD at 250 mA current?
The output low voltage at 250 mA current is 1.0 V.
- What package styles are available for the L5991AD?
The L5991AD is available in DIP16 and SO16 package styles.
