NCP1237: Fixed Frequency Current Mode PWM Controller

The NCP1237 is a new generation of the NCP12xx fixed-frequency current-mode controllers featuring Dynamic Self-Supply (DSS), pin to pin compatible with the previous generation. The DSS function greatly simplifies the design of the auxiliary supply and the VCC capacitor by activating the internal start-up current source to supply the controller during transients. Due to its proprietary Soft-Skip™ mode combined with frequency foldback, the controller exhibits excellent efficiency in light load condition while still achieving very low standby power consumption. This Soft-Skip feature also dramatically reduces the risk of acoustic noise, which enables the use of inexpensive transformers and capacitors in the clamping network. The NCP1237 features a dual-level timer-based fault detection that controls the amount of transient peak power that the controller can deliver for a limited time. Internal frequency jittering, ramp compensation, and a versatile latch input make this controller an excellent candidate for converters where ruggedness and components cost are the key constraints. In addition, the controller includes a new high voltage circuitry that combines a startup current source and a brown-out / line OVP detector able to sense the input voltage either from the rectified ac line or the dc filtered bulk voltage. Finally, due to a careful design, the precision of critical parameters is well controlled over the entire temperature range (-40°C to +125°C), enabling easier design and increased safety (e.g. ±5% for the peak current limit, ±7% for the oscillator).

技术特性

Timer−Based Transient Power and Overload
Protections with Auto−Recovery (Option B) or Latched
(Option A) Operation
High−Voltage Current Source with DSS with Built−in
Brown−out and Line Overvoltage Protections
Fixed−Frequency Current−Mode Operation with
Built−in Ramp Compensation
Frequency Jittering for a Reduced EMI Signature
Adjustable Overpower Compensation
Latch−off Input for Severe Fault Conditions, with
Direct Connection of an NTC for Overtemperature
Protection (OTP)
Protection Against Winding Short−Circuit
Frequency Foldback transitioning into Soft−Skip for
Improved Performance in Standby

优势

Overload protection independent of the auxiliary winding
Reduced EMI signature
Improved Performance in Standby

应用

Ac-dc Adapters for Notebooks, LCD, and Printers
Offline Battery Chargers
Consumer Electronic Power Supplies
Auxiliary/Housekeeping Power Supplies

封装图 PACKAGE DIMENSIONS

评估板信息

评估板	状况	无铅(Pb-free)	简短说明
NCP1237PRINTGEVB	Active		32W, 32V PRINTER ADAPTER

订购信息 Ordering Information

产品

状况

Compliance

具体说明

封装

MSL*

容器

预算价格 (1千个数量的单价）

类型

外形

类型

数量

NCP1237AD65R2G

Active

Pb-free

Halide free

Fixed Frequency Current Mode PWM Controller

SOIC-8

751U

Tape and Reel

2500

$0.6667

NCP1237BD65R2G