Tl494 Circuit Diagram [verified] [UHD 8K]
A Buck converter (step-down regulator) is the perfect beginner circuit and the best way to see the pin-level operation in action.
These are operational amplifiers with high gain. They monitor output voltage or current, feeding data back to the PWM comparator to regulate the duty cycle.
Compensation/Feedback input; accesses the error amplifier outputs for loop stability
: Pin 4 provides a way to set a minimum "off-time" between pulses to prevent overlap in push-pull stages. tl494 circuit diagram
For (Pin 13 to GND), the output frequency equals the oscillator frequency:
. Operating at higher voltages increases internal power dissipation, which may require localized PCB copper pours for thermal management. Keep the timing components (
ceramic bypass capacitor directly between VCC (Pin 12) and GND (Pin 7) as close to the IC body as possible to filter out high-frequency switching noise. A Buck converter (step-down regulator) is the perfect
provides 5V ± 5% up to 10mA. Use it for potentiometers and error amp references.
+---U---+ 1IN+ | 1 16 | 2IN- 1IN- | 2 15 | 2IN+ FEED | 3 14 | REF (5V) DTC | 4 13 | OUTPUT CTRL CT | 5 12 | VCC RT | 6 11 | C2 GND | 7 10 | E2 C1 | 8 9 | E1 +-------+ Pin Functions
+-------------------+ | TL494 | | | | Pin 13 ------+----> To Pin 14 (VREF) [Push-Pull Mode] | | Driver Q1 <---+-- Pin 9 (E1) | (N-Channel) | Pin 8 (C1) -----+----> To VCC | | Driver Q2 <---+-- Pin 10 (E2) | (N-Channel) | Pin 11 (C2) ----+----> To VCC +-------------------+ Keep the timing components ( ceramic bypass capacitor
The oscillator (pins 5 & 6) generates a sawtooth wave. The PWM comparator compares this sawtooth to the error signal from Amps 1 & 2. The output logic then drives the two transistors (Q1/Q2). Pin 4 (DTC) adds an offset to the sawtooth, limiting max duty cycle.
: Connected to pin 4, this comparator provides a fixed or adjustable minimum "off" period. This is critical in push-pull configurations to prevent "shoot-through," where both switching transistors are on at the same time, causing a short circuit. Output Steering Flip-Flop
is connected to a potentiometer to control the pulse width. Pin 13 is grounded for single-ended output. Outputs (E1/E2) drive an external MOSFET. 2. Buck Converter Circuit The TL494 is excellent for step-down converters.
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