IC REG CTRLR PWM CM 14-SOIC UC3844 is a current PWM controller.
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Aug 9, 2021
Felix Ferdinand
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#138 UC3844 Current Mode SMPS Circuit - Circuit Explained with Troubleshooting
IC REG CTRLR PWM CM 14-SOIC
UC3844 is a current PWM controller. This article mainly introduce its uses, pinout, datasheet and other detailed information about On Semiconductor UC3844.
UC3844D
The UC3844 is fixed frequencycurrent-mode PWM controller. It is specially designed for Off-Line and DC to DC converter applications with minimum external components.
These integrated circuits feature a trimmed oscillator for precise duty cycle control, a temperature compensated reference, high gain error amplifier, current sensing comparator and a high current totempole output for driving a Power MOSFET.
The UC3844 have UVLO thresholds of 16V (on) and 10V (off) and can operate with 50% duty cycle.
Symbol
Footprint
3D Model
1.Current-Mode PWM controller
2.Operating Voltage: 12V to 28V
3.Output pin current: 200 mA
4.Switching Frequency: 500 kHz
5.Duty Cycle - Max: 100 %
6.Operating Supply Current:25 mA
7.Optimized for Off-line and DC-to-DC Converters
8.High-Current Totem-Pole Output
9.Output Deadtime Adjustable from 50% t
10.Low Start Up Current (<1mA)
11.Automatic Feed Forward Compensation
12. Pulse-by-pulse Current Limiting
13.Enhanced Load Response Characteristics
14.Under-voltage Lockout With Hysteresis
15.Double Pulse Suppression
16.Internally Trimmed Bandgap Reference
17.Low RO Error Amp
18.Maximum Duty Clamp
19.UVLO With Hysteresis
ON Semiconductor UC3844D technical specifications, attributes, parameters and parts with similar specifications to ON Semiconductor UC3844D.
ON Semiconductor UC3844D technical specifications, attributes, parameters and parts with similar specifications to ON Semiconductor UC3844D.
| Product Attribute | Attribute Value | |
|---|---|---|
| Mount | Surface Mount | |
| Mounting Type | Surface Mount | |
| Package / Case | 14-SOIC (0.209, 5.30mm Width) | |
| Number of Pins | 14Pins | |
| Operating Temperature | 0°C~70°C TA | |
| Packaging | Tube | |
| Published | 2002 | |
| JESD-609 Code | e0 | |
| Part Status | Obsolete | |
| Moisture Sensitivity Level (MSL) | 1 (Unlimited) | |
| Number of Terminations | 14Terminations | |
| ECCN Code | EAR99 | |
| Terminal Finish | Tin/Lead (Sn/Pb) | |
| Terminal Position | DUAL | |
| Terminal Form | GULL WING |
| Product Attribute | Attribute Value | |
|---|---|---|
| Peak Reflow Temperature (Cel) | 240 | |
| Time@Peak Reflow Temperature-Max (s) | 30 | |
| Base Part Number | UC3844 | |
| Function | Step-Up, Step-Up/Step-Down | |
| Number of Outputs | 1Output | |
| Output Voltage | 5.1V | |
| Output Type | Transistor Driver | |
| Input Voltage-Nom | 15V | |
| Analog IC - Other Type | SWITCHING CONTROLLER | |
| Operating Supply Current | 17mA | |
| Nominal Supply Current | 17mA | |
| Output Configuration | Positive | |
| Output Current | 1A | |
| Voltage - Supply (Vcc/Vdd) | 10V~30V | |
| Control Features | Frequency Control |
| Product Attribute | Attribute Value | |
|---|---|---|
| Topology | Boost, Flyback | |
| Control Mode | CURRENT-MODE | |
| Frequency - Switching | Up to 500kHz | |
| Input Voltage (Max) | 25V | |
| Control Technique | PULSE WIDTH MODULATION | |
| Rise Time | 45ns | |
| Synchronous Rectifier | No | |
| Fall Time (Typ) | 35 ns | |
| Switcher Configuration | SINGLE | |
| Max Duty Cycle | 50 % | |
| Duty Cycle (Max) | 48% | |
| Length | 8.65mm | |
| Width | 3.9mm | |
| RoHS Status | RoHS Compliant |
The UC3844 IC is a current Mode PWM Controller, meaning it can be used to provide a constant current by varying the output voltage to the load.
This IC features a trimmed oscillator for precise duty cycle control, a temperature compensated reference, a high gain error amplifier, a current sensing comparator, and a high current totem pole output for driving a Power MOSFET. The UC3842 and UC3844 have the same UVLO thresholds of 16V (on) and 10V (off).
The UC3844 can be used to regulate or limit current in applications like SMPS, RPS, DC-DC Converters, Line voltage regulators, etc. So if you are looking for an IC to produce PWM signals for controlling a power switch based on the current flowing through the circuit, then this IC might be the right choice for you.
Using UC3844 in a circuit is very simple as it requires a minimum number of components. A sample application circuit from the UC3844 datasheet is shown below.
The input voltage to the VCC pin should be 12V to 28v. The output pin of the IC is connected to the gate driver circuit of the Power switch which is to be switched. The VFB (Voltage feedback) pin acts as feedback based on which the PWM signal is controlled. A shunt resistor is used to monitor the change in current in the circuit, and then this difference voltage across the shunt is provided to the feedback pin. VREF is used to provide charging current to the oscillator timing capacitor through the timing resistor. It is important for reference stability that VREF is bypassed to GROUND with a ceramic capacitor connected as close to the pin as possible.
1.DC-DC converter circuits
2.Electronics power supply
3.Battery drain circuit
4.Load machines
5.SMPS (Switch Mode Power Supplies) circuits
ON Semiconductor is a semiconductor supplier company, Products include power and signal management, logic, discrete, and custom devices for automotive, communications, computing, consumer, industrial, LED lighting, medical, military/aerospace and power applications. ON Semiconductor runs a network of manufacturing facilities, sales offices and design centers in North America, Europe, and the Asia Pacific regions. Its headquarter is in Phoenix, Arizona.
Download datasheets and manufacturer documentation for ON Semiconductor UC3844D.
Download datasheets and manufacturer documentation for UC3844D
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