OB2263
High-performance PWM controller for offline power supplies with low standby power
Product Overview
Description
The OB2263 is a highly integrated PWM controller designed for offline power supply applications. It features a high-voltage startup circuit, built-in leading edge blanking, and comprehensive protection functions including OVP, OCP, and OTP.
With its low startup current and operating current, the OB2263 achieves excellent standby power performance, meeting international energy efficiency standards. The internal frequency jittering helps reduce EMI, simplifying filter design and reducing system cost.
The OB2263 is ideal for adapter applications, open-frame power supplies, and auxiliary power supplies where cost-effectiveness and reliability are critical requirements.
Product Series
OB
Primary Application
AC/DC adapters
Key Features
- High-voltage startup circuit
- Low startup current (< 20uA)
- Built-in frequency jittering for EMI reduction
- Cycle-by-cycle current limiting
- Over-voltage protection (OVP)
- Over-temperature protection (OTP)
- Auto-restart protection
Specifications
| Input Voltage | 85V - 265V AC |
|---|---|
| Output Power | Up to 60W |
| Switching Frequency | 65 kHz |
| Standby Power | < 0.1W |
| Operating Temperature | -40°C to +85°C |
| Package | SOT23-6, DIP-8 |
Applications
AC/DC adapters
Electronic system design
Open-frame power supplies
Electronic system design
Auxiliary power supplies
Electronic system design
Battery chargers
Battery and charging management
LED power supplies
Electronic system design
FAE Expert Insights
"The OB2263 is a workhorse PWM controller that I've used in countless adapter designs. Its high integration reduces BOM cost significantly - the built-in high-voltage startup eliminates external startup resistors. The frequency jittering really works for EMI; I've passed CISPR22 Class B with minimal filtering. Standby power is excellent, easily meeting DoE Level VI requirements. One tip: pay attention to the current sense resistor layout - keep the trace to the CS pin short and away from the MOSFET drain to avoid noise issues. Overall, a reliable, cost-effective choice for sub-60W applications."
— Senior FAE - Power Supply Applications, BeiLuo
Frequently Asked Questions
What is the maximum output power of OB2263?
The OB2263 can support up to 60W output power in flyback topology with appropriate external MOSFET and transformer design. For higher power applications, consider using external MOSFETs with higher current ratings.
Design for 20-30% power margin below maximum rating for reliable operation and thermal management.
How do I achieve low standby power with OB2263?
OB2263 achieves low standby power through its low startup current and operating current design. Use a high-value startup resistor (2M-4M ohm range) and minimize the VCC capacitor value while ensuring stable operation. The built-in frequency reduction at light load also helps reduce switching losses.
Follow reference design guidelines for startup resistor and VCC capacitor selection.
What transformer design is recommended for OB2263?
OB2263 works with standard flyback transformer designs. Key considerations include proper core selection for power level, appropriate turns ratio for desired output voltage, and sufficient winding margins for safety isolation. On-Bright provides transformer design guidelines in their application notes.
Start with reference design transformer specifications and adjust based on your specific requirements.
How do I set the current limit for OB2263?
Current limit is set by the current sense resistor connected between the MOSFET source and ground. The CS pin threshold is typically 1V. Calculate Rsense = 1V / Ipeak, where Ipeak is the desired peak current. Include margin for component tolerances.
Calculate sense resistor based on maximum output power and transformer design; verify with actual testing.
What EMI filtering is required with OB2263?
OB2263's internal frequency jittering reduces conducted EMI, simplifying filter design. A typical common-mode choke with X and Y capacitors is usually sufficient for most applications. Follow CISPR22/EN55022 guidelines for filter component selection.
Start with reference design filter values; adjust based on EMI testing results.