. Filtering oscillator controlled by precision frequency

. When the frequency of the oscillator is 250kHz

. The current mode runs to 500kHz

.

UC384XBFAMILYFCONTROLICS provides necessary functional fixed frequency current mode control solutions to achieve offline or from DC to DC. The minimum number of external parts. The internal implementation circuit includes a fine -tuning oscillator, which is used for accurate duty cycle ratio under voltage lock; the output startup current is less than 0.5mA; a fine -tuning reference, the accuracy amplifier input used for errors, logic to ensure operation, a pulse width modulation A comparator with current limit control can also be provided, as well as a totem column output stage or a peak of the exchange. The output level is suitable for driving the N -channel MOSFET, which is very low in the shutdown state.

The difference between this family member is the lack of voltage lock threshold and maximum load cycle range.

and UC3844B have the ideal UVLO threshold of 16V (open) and 10V (level) suitable for corresponding linear applications, such as the three old models of the European 3843banduc3845Bare8.5 and 7.9, UC3842B and UC3843B The working cycle is close to 100%. From zero to lt; 50%from UC3844 band UC3845BBY to add an internal trigger to make the output of each clock cycle of blank blank.

Fragics (triggers are only used for UC3844B and UC3845B) Open ring test circuit.

The peak value of the capacitance load requires cautious grounding technology. The electric container should be closely connected in a single point ground to insert the foot 5. The transistor and the KΩ potential are measured to sample oscillator waveforms and apply adjusted slopes to the pin 3.

10K 20K 30K 50K 100K 100K 300K 500K FOSC (Qianhe)

The frequency of timing resistance and oscillator

Output dead area time The relationship between the discharge current of the oscillator

The relationship between the oscillator and the TEM temperature.

The relationship between the increasing loop of the large and the phase and the frequency of the error placing the large device.

Reference voltage change and source current.

Temperature.

Output saturated voltage VS.

Output waveform.

oscillator and output waveform.

1.0V as the maximum value ≈RS

may require a small RC filtering The device to suppress the switch transient.

slope compensation technology

Soft start and error amplifier output duty ratio