UCC38501
- Combines PFC and Downstream Converter Controls
- Controls Boost Preregulator to Near-Unity Power Factor
- Accurate Power Limiting
- Improved Feedforward Line Regulation
- Peak Current-Mode Control in Second Stage
- Programmable Oscillator
- Leading-Edge/Trailing-Edge Modulation for Reduced Output Ripple
- Low Start-up Supply Current
- Synchronized Second Stage Start-Up, with Programmable Soft-start
- Programmable Second Stage Shutdown
The UCC2850x family provides all of the control functions necessary for an active power-factor-corrected preregulator and a second-stage dc-to-dc converter. The controller achieves near-unity power factor by shaping the ac input line current waveform to correspond to the ac input-line voltage using average current-mode control. The dc-to-dc converter uses peak current-mode control to perform the step-down power conversion.
The PFC stage is leading-edge modulated while the second stage is trailing-edge synchronized to allow for minimum overlap between the boost and PWM switches. This reduces ripple current in the bulk-output capacitor.In order to operate with over three-to-one range of input-line voltages, a line feedforward (VFF) is used to keep input power constant with varying input voltage. Generation of VFF is accomplished using IAC in conjunction with an external single-pole filter. This not only reduces external parts count, but also avoids the use of high-voltage components, offering a lower-cost solution. The multiplier then divides the line current by the square of VFF.
The UCC2850x PFC section incorporates a low offset-voltage amplifier with 7.5-V reference, a highly-linear multiplier capable of a wide current range, a high-bandwidth, low offset-current amplifier, with a novel noise-attenuation configuration, PWM comparator and latch, and a high-current output driver. Additional PFC features include over-voltage protection, zero-power detection to turn off the output when VAOUT is below 0.33 V and peak current and power limiting.
The dc-to-dc section relies on an error signal generated on the secondary-side and processes it by performing peak current mode control. The dc-to-dc section also features current limiting, a controlled soft-start, preset operating range with selectable options, and 50% maximum duty cycle.
The UCC28500 and UCC28502 have a wide PFC-UVLO threshold (16.5 V/10 V) for bootstrap bias supply operation. The UCC28501 and UCC28503 are designed with a narrow UVLO range (10.5 V/10 V) more suitable for fixed bias operation. The UCC28500 and UCC28501 have a narrow UVLO threshold for PWM stage (to allow operation down to 75% of nominal bulk voltage), while the UCC28502 and UCC38503 are configured for a much wider operation range for the PWM stage (down to 50% of bulk nominal voltage).
Available in 20-pin N and DW packages.
기술 문서
| 유형 | 직함 | 날짜 | ||
|---|---|---|---|---|
| * | Data sheet | BiCMOS PFC/PWM Combination Controller datasheet (Rev. C) | 2001/11/08 | |
| Application note | Avoiding Audible Noise at Light Loads When Using Leading Edge Triggered PFC Con (Rev. C) | 2011/04/13 | ||
| Application note | A New Synchronization Circuit for Power Converters (Rev. A) | 2010/04/21 | ||
| Application note | Bootstrap Circuit for Green Mode Applications | 2006/01/27 | ||
| Application note | Startup Current transient of the Leading Edge Triggered PFC Controllers | 2004/06/30 | ||
| Application note | Accurate PWM Duty Cycle Clamp | 2002/01/25 | ||
| Application note | DN-66 UC3854A/B and UC3855A/B Provide Power Limiting with Sinusoidal Input (Rev. A) | 2001/11/06 |
설계 및 개발
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주문 및 품질
- RoHS
- REACH
- 디바이스 마킹
- 납 마감/볼 재질
- MSL 등급/피크 리플로우
- MTBF/FIT 예측
- 물질 성분
- 인증 요약
- 지속적인 신뢰성 모니터링
- 팹 위치
- 조립 위치