مدار مجتمع (آی سی) آی‌سی مدیریت توان (پی‌ام‌آی‌سی) مدیریت توان ویژه

Product Attributes

Introduction

The IS801 is a monolithic oscillator/power-driver, which is designed for small form factor, isolated power supplies in isolated interface applications. A low-profile, center-tapped transformer primary from a 3.3V or 5V DC power supply can be driven by IS801 while the secondary can be wound to provide any isolated voltage based on transformer turns ratio. The IS801 provides the complementary output signals to drive the ground referenced N-channel power switches. In addition to internal break-before-make logic between two switches, the IS801 is also integrated with VCC undervoltage protection and thermal shutdown protection. The added spread spectrum clocking can help pass the system EMI test. The IS801 is available in a small SOT23-5 package, and is specified for operation at temperatures from -40°C to 125°C.

The IS801 is a transformer driver designed for low-cost, small form-factor, isolated DC-DC converters utilizing the push-pull topology. The device consists of an oscillator followed by the gate driver that includes a frequency divider and a break-before-make (BBM) logic, provides two complementary output signals which alternately turn the two output transistors on and off. The oscillator’s output frequency is divided down by an asynchronous divider that can output two complementary, 50% duty cycle output signals. The break-before-make logic is implanted by injecting a dead-time between the high-pules of the two output signals. As shown in the functional block diagram, either of the two gates can output logic high, hence a short time period is a must when both signals are low and both transistors are high-impedance. This short time period is known as break-before-make time, which can avoid shorting out both ends of the primary. To make it easier to pass system EMI tests, the spread spectrum scheme is also added in oscillator of IS801. In addition, the IS801 is integrated with VCC undervoltage fault and the thermal shutdown modules.

Features

• Push-pull driver for small transformers
• Single 3.3V or 5V supply
• High primary-side current drive: 5V supply: 500mA (max) 3.3V supply: 500mA (max)
• Low ripple on rectified output permits small output capacitors
• VCC undervoltage detect
• Spread spectrum clocking for EMI
• Thermal shutdown protection
• Small SOT23-5 package

Applications

• Isolated interface power supply for CAN, RS 485, RS-422, RS-232, SPI, I2C, Low-Power LAN
• Industrial automation
• Process control
• Medical equipment