Catalog
Aux Controller for Secondary Micro Systems
Key Features
• * HV Startup Capability (500V Continuous, 700V Transient w/series 10K Resistor)
• * Internal Open-Loop, Peak Current-Mode (PCM) Current Regulator for Start-up (w/Few External Components) w/Integrated Robust Gate Driver
• * Current Regulator (Constant Off Time, 21us)
• * Protection Against Continuous Conduction Mode (CCM) of Operation
• * Programmable Low-Frequency Oscillator (LFO) Period to Set Startup Power
• * Able to Accept External PWM Commands from a Secondary Controller via Isolator (Various)
• * Undervoltage Lockout (UVLO) and Overvoltage Lockout (OVLO) Protections, Cycle-by-Cycle Current Limiting, Overtemperature Protection (Thermal Shutdown)
• * Sleep and Wake-up Commands, w/Low Standby Power (<15 mW)
• * Package: 7-Lead SOIC
Description
AI
The MCP1012 is used as a primary-side start-up IC for starting
an offline auxiliary switching supply working in conjunction with a
secondary-side controller. The MCP1012 does not linearly regulate the power converter,
but rather a secondary-side controller (digital and/or analog) accurately
linear regulates using sophisticated adaptive control schemes that enhance
performance and efficiency.
The primary function of the MCP1012 are to provide startup
of the flyback converter using an internal open-loop, peak current-mode current
regulator. It does this by accepting PWM
commands via an isolation medium (s.a. a pulse transformer, opto, or other) from
a secondary-side controller. It integrates
various protection features, including an undervoltage lockout (UVLO) and overvoltage
lockout (OVLO) protection, and overtemperature protection (OTP.) Additionally, the MCP1012 provides peak cycle-by-cycle
current limiting both when under control of its internal current regulator or under
control of the secondary-side controller.
