Description

The SG3842D is an AC DC converter and offline switcher electronic component designed for off-line fixed frequency, current-mode switching power supplies with a minimum number of external components. Its current-mode architecture exhibits improved line regulation, improved load regulation, pulse-by-pulse current limiting, and inherent protection of the power supply output switch. The bandgap reference is trimmed to ±1% over temperature, and the oscillator discharge current is trimmed to less than ±10%. The SG3842D has under-voltage lockout, current limiting circuitry, and start-up current of less than 1mA.

Specifications and features

• Optimized for off-line control
• Low start-up current (<1mA)
• Automatic feed forward compensation
• Trimmed oscillator discharge current
• Pulse-by-pulse current limiting
• Enhanced load response characteristics
• Under-voltage lockout with 6V hysteresis (SG1842 only)
• Double-pulse suppression
• High-current totem-pole output (1AMP peak)
• Internally trimmed bandgap reference
• 500KHZ operation
• Undervoltage lockout: SG1842 - 16 volts, SG1843 - 8.4 volts
• Low shoot-through current <75mA over temperature

Application Scenarios

The SG3842D can be used in various applications that require an AC DC converter or an offline switcher, such as:

• Power supplies for industrial equipment
• Telecommunication systems
• Consumer electronics
• Lighting systems

Comparison

• Improved line and load regulation
• Pulse-by-pulse current limiting and inherent protection of the power supply output switch
• Internally trimmed bandgap reference
• Enhanced load response characteristics
• High-current totem-pole output

• Undervoltage lockout is limited to 16 volts for SG1842 and 8.4 volts for SG1843
• Double-pulse suppression may not be necessary in all applications