voltage converter

Voltage Converter 2 Schematic Circuit Diagram

Efficient Voltage Converter 2 with Switch-Mode Advantage

Voltage converter 2: While a standard regulator can easily reduce a 9.5–24 V direct voltage to 5 V, the described converter holds a distinct advantage as a switch-mode type, minimizing heat dissipation. Despite being capable of handling peaks of up to 750 mA, its maximum steady output current at 5 V is 250 mA. This efficiency is achieved through the implementation of a Motorola ‘Type MC34161 circuit, enhanced by the addition of a power stage (T1). Inductors LI, C5, and D1 work in tandem to eliminate any output ripple.

Circuit Configuration and Control Mechanism

The converter’s core is based on the Motorola ‘Type MC34161 circuit, complemented by the inclusion of a power stage represented by T1. Inductors LI, C5, and D1 collaborate to eliminate output ripple. The internal comparator at pin 2 of IC1 is linked to the converter’s output via potential dividers R4-R5, enabling continuous monitoring of the output voltage. The second comparator (pin 3) serves in the oscillator circuit, connecting directly to pin 6 and to pin 5 via R3-C3. Upon the supply being switched on, the converter’s output, and thus the voltage at pin 2, is initially 0, allowing normal oscillator operation.

Transistor T1 facilitates the charging of C5 via L1 when it is off, ensuring an energy supply to C5 via D1. Once C5’s terminal voltage reaches a sufficiently high level, the internal comparator at pin 2 changes state, deactivating the oscillator through pin 6, thereby turning off T1. After C5 discharges to a point where its terminal voltage falls below the preset level, the oscillator is reactivated, and C5 undergoes recharging via T1.

Voltage converter 2 Schematic diagram

Switching Frequency Determined by L1 and C5 Values

The switching frequency is dictated by the values assigned to L1 and C5. With the provided values, an input voltage of 12 V, and a load current of 250 mA, the resulting frequency is 18 kHz. However, when utilizing larger inductances and 4F input voltages, the frequency experiences a reduction. It is crucial to ensure that all earth connections are directed to the negative side of C5, following the indicated configuration in the diagram.

Customizing Turns for Standard Triac Choke

The inductor takes the form of a standard triac choke, necessitating the addition of a specific number of turns. If the choke’s inductance is denoted as L (in pH) and it originally had n turns, the required number of turns (n’) for the current inductor can be calculated using the formula n’ = n √ (470/L). This adjustment ensures the inductor aligns with the specific requirements of the present circuit.

Voltage converter 2 Schematic diagram

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