UC3841N ,Programmable, Off-Line, PWM ControllerMAXIMUM RATINGS Supply Voltage, +V (Pin 15) (Note 2) Operating Junction Temperature . . . . . . . . ..
UC3842 ,SMPS ControllerUC2842/3/4/5UC3842/3/4/5 CURRENT MODE PWM CONTROLLEROPTIMIZED FOR OFF-LINE AND DC TO DC.CONVERTERS ..
UC3842A ,Current mode PWM control circuit.UC284XAUC384XAHIGH PERFORMANCE CURRENT MODE PWM CONTROLLERNOT FOR NEW DESIGN1
UC3842A# ,Current mode PWM control circuit.Maximum ratings applied to the device are individual stress limitvalues (not normal operating condi ..
UC3842AD ,SMPS ControllerUC3842A, UC3843A,UC2842A, UC2843AHigh PerformanceCurrent Mode ControllersThe UC3842A, UC3843A serie ..
UC3842AD1013TR ,HIGH PERFORMANCE CURRENT MODE PWM CONTROLLERFEATURESFigure 1. Package■ TRIMMED OSCILLATOR DISCHARGE CURRENT■ CURRENT MODE OPERATION TO 500kHz A ..
UMN10 N , Switching diode
UMN10N , Switching diode
UMN1N , 0.025A , 80V Plastic-Encapsulated Switching Diode
UMN1N , 0.025A , 80V Plastic-Encapsulated Switching Diode
UMP1N , Switching diode
UMT2222A , NPN Medium Power Transistor (Switching)
UC3841J-UC3841N
Programmable, Off-Line, PWM Controller
UC1841
UC2841
UC3841Programmable, Off-Line, PWM Controller All Control, Driving, Monitoring, and
Protection Functions Included Low-current, Off-line Start Circuit Voltage Feed Forward or Current
Mode Control Guaranteed Duty Cycle Clamp PWM Latch for Single Pulse per Period Pulse-by-Pulse Current Limiting Plus
Shutdown for Over-Current Fault No Start-up or Shutdown Transients Slow Turn-on Both Initially and After
Fault Shutdown Shutdown Upon Over- or
Under-Voltage Sensing Latch Off or Continuous Retry After
Fault PWM Output Switch Usable to 1A
Peak Current 1% Reference Accuracy 500kHz Operation 18 Pin DIL Package
The UC1841 family of PWM controllers has been designed to increase
the level of versatility while retaining all of the performance features of
the earlier UC1840 devices. While still optimized for highly-efficient boot-
strapped primary-side operation in forward or flyback power converters,
the UC1841 is equally adept in implementing both low and high voltage
input DC to DC converters. Important performance features include a
low-current starting circuit, linear feed-forward for constant volt-second
operation, and compatibility with either voltage or current mode topologies.
In addition to start-up and normal regulating PWM functions, these de-
vices include built in protection from over-voltage, under-voltage, and
over-current fault conditions with the option for either latch-off or automat-
ic restart.
While pin compatible with the UC1840 in all respects except that the po-
larity of the External Stop has been reversed, the UC1841 offers the fol-
lowing improvements:
1. Fault latch reset is accomplished with slow start discharge rather
than recycling the input voltage to the chip.
2. The External Stop input can be used for a fault delay to resist
shutdown from short duration transients.
3. The duty-cycle clamping function has been characterized and
specified.
The UC1841 is characterized for -55°C to +125°C operation while the
UC2841 and UC3841 are designed for -25°C to +85°C and 0°to +70°C,
respectively.
BLOCK DIAGRAM
DESCRIPTIONFEATURES
