I came across an inverter design that is built with CD4047, which is a versatile CMOS IC commonly used as an astable multivibrator or flip-flop to generate stable square wave signals for driving MOSFETs in push-pull inverter configurations. It is similar to the 555 Timer in that it can be configured as an astable multivibrator to generate square wave signals, but unlike the 555, the CD4047 offers more accurate frequency stability, a precise 50% duty cycle, and complementary outputs, making it better suited for inverter and timing applications where balanced switching is essential.
The CD4047 Inverter circuit diagram is shown below.
Here’s a clear breakdown of the inverter circuit:
๐ง 1. CD4047 as Astable Oscillator
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The CD4047 IC is configured as an astable multivibrator to generate a 50 Hz square wave.
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Timing is set by the RC network: . For example, using 4.7 ยตF and ~1 kฮฉ gives ~47 Hz, close enough for basic loads.
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It provides complementary 50% duty outputs on pins 10 and 11, perfect for driving two switching elements alternately.
๐ 2. Push–Pull MOSFET Stage
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Each output from CD4047 goes to the gate of an N-channel MOSFET IRFZ44, forming a push–pull pair.
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These MOSFETs alternately energize each half of the transformer's primary winding.
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Proper heatsinking is vital, as they handle significant current.
๐ 3. Center‑Tapped Transformer
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A 12–0–12 V transformer (primary at 12 V, secondary steps up to 220 V AC) is used.
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MOSFET1 drives one half‑winding, creating one half‑cycle, MOSFET2 drives the other, creating the opposite half‑cycle.
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Result: a square wave 220 VAC output at 50 Hz.
In the above circuit, the CD4047 is configured in astable multivibrator mode.
