By using the TL494 to drive a high-side MOSFET, you can create a highly efficient step-down converter. The chip ensures that even as your battery drains, the output voltage remains exactly where you set it. Pure Sine Wave Inverters
| Pin # | Name | Function | | :--- | :--- | :--- | | 1 | Non-Inverting Input (Error Amp 1) | Usually connected to the voltage feedback. | | 2 | Inverting Input (Error Amp 1) | Connected to a reference voltage. | | 3 | Feedback/PWM Comp | Common point for compensation networks. | | 4 | Dead-Time Control (DTC) | Voltage here controls dead time (0V to 3V). | | 5 | CT | Capacitor for timing oscillator. | | 6 | RT | Resistor for timing oscillator. | | 7 | GND | Ground. | | 8 | C1 | Collector of Output Transistor 1. | | 9 | E1 | Emitter of Output Transistor 1. | | 10 | E2 | Emitter of Output Transistor 2. | | 11 | C2 | Collector of Output Transistor 2. | | 12 | VCC | IC Supply Voltage. | | 13 | Output Control | Selects mode: High = Push-pull, Low = Single-ended. | | 14 | REF | 5V Precision Reference Output. | | 15 | Inverting Input (Error Amp 2) | Usually used for current limiting. | | 16 | Non-Inverting Input (Error Amp 2) | Connected to current sense shunt. | tl494 circuit diagram
The TL494 operates as follows:
In a functional analysis, the diagram shows that the capacitor CT is charged by the current through RT and discharged internally. This creates a sawtooth waveform on the timing capacitor. This waveform is the timing clock for the PWM. It feeds into the comparator section, establishing the "ramp" against which the control voltage is compared. The visual simplicity of two pins on the diagram belies the complex timing generation that dictates the switching speed of the entire power supply. By using the TL494 to drive a high-side
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