1. The Role of PWM Modulator:
To comprehend the functioning of the PWM modulator effectively, it is essential to break it down into distinct blocks. The pivotal initial block is the triangular signal generator, comprising an integrator facilitated by the operational amplifier THS4271.
2. Triangular Signal Generation:
Within this setup, a continuous flow of current charges the capacitor, leading to a linear rise in voltage. Conversely, when discharging occurs, a linear voltage decline is observed. The charging or discharging state of the capacitor is governed by the swift operational amplifier THS4271, functioning as a comparator. The critical operational amplifier rollover level is established by a composite divider, R96 and R97. The use of a fast operational amplifier, instead of a comparator, is due to its end-double-acting degree, ensuring identical voltage drops at the end transistors in both output voltage levels. Another operational amplifier between the integrator and the comparator is used solely to rotate the phase of the triangular signal. The deliberate selection of THS4271 operational amplifiers is due to their marginal frequency characteristics.
3. End Stage Circuitry:
The final segment of the circuit comprises the end stage, including the IR2110 driver marked as IC10 and IC11, along with MOSFET transistors labeled T1 to T4. This section operates as a two-terminal degree involved in the půlmůstkového configuration. The transistors are controlled by conflicting signals, ensuring opposing voltage levels at their outputs. These output voltage levels from transistor pairs are linked to a second-order filter output, consisting of coils L1 and L2, and capacitors C48 to C50. The coils, wound with 1.6 mm diameter wire around the iron core T 157-26, operate within a frequency range of 0 to 1 MHz. A nonlinear amplifier and a compensation RC filter, utilizing resistors R42 and R43 and capacitor C54, are connected in parallel to the audio output. The compensation filter’s purpose is to minimize speaker impedance, enabling the speaker to deliver enhanced performance, while the nonlinear amplifier complements the overall circuit.
4. Simplified Description:
In simpler terms, this 2-channel 400W class amplifier (IR2110 class D amplifier circuit) integrates components such as the NE555 timer, LM393 op-amp-based preamplifier, PWM module (LM319, THS4271), and IR2110 MOSFET driver circuit. These components are organized into separate modules. The IR2110 MOSFET operates on a single working voltage of 65V DC and forms part of an 800W Class D amplifier project. While the circuit’s complexity might seem daunting, detailed calculations, circuit design formulas, and PCB layouts can significantly aid in comprehending and implementing similar Class D amplifier projects.
SCHEMATICS CIRCUIT DIAGRAM