The function of the PWM modulator For clarity of explanation of the function of the entire PWM modulator it is advisable to split it into a few blocks away. The first and most important block is the generator of triangular signal, which consists of the integrator formed by the operational amplifier THS4271.
A constant stream of the condenser ensures linear increase the voltage on this capacitor in the case that it is charging. In the opposite the case of the capacitor can be observed a linear decline in voltage. Whether a capacitor is charging or discharges governed by the fast operational amplifier THS4271 in the function of the comparator. The decisive level of rollover of the operational amplifier is formed by a divider a composite of the R96 and R97. The reason for using a fast operational amplifier instead of the comparator lies in its the involvement of end-double-acting degree, which ensures the same voltage drop at the end transistors of the operational amplifiers in both levels of the output voltage. Operational amplifier inserted between the integrator and a comparator is used only to rotate the phase of the triangular signal. Operational amplifiers THS4271 are chosen deliberately due to its marginal frequency.
The first described part of the circuit is the very end stage, which is formed driver IR2110 marked as IC10 and IC11 and further transistors of type MOSFET with a designation T1 up to T4. This is basically a two terminal degree involved in the půlmůstkového involvement, which are controlled by the conflicting signals and thus on its outputs reach always a tension in the opposite level. The output voltage levels of the pairs of transistors are connected to the output of the filter the second order, which is formed by the coils L1 and L2 and capacitors C48 to C50. The threads of the coils L1 and L2 will be wound with wire of a diameter of 1.6 mm to make the iron core with the designation T 157-26, in which the operating frequency varies in the range ( 0 – 1 ) MHz. In parallel to the audio output a nonlinear amplifier is connected to the compensation RC filter, which is implemented using resistors R42 and R43 and the capacitor C54. The compensation filter has the task to reduce the impedance connected the speaker to the end-amplifier to the speaker could deliver greater performance.
Or in simple words we can also explain this in simple words that the 2 channel 400w class amplifier (ir2110 class d amplifier circuit) circuit consists of the NE555 timer, the preamplifier based on LM393 opams, the PWM module ( LM319, THS4271 ) and the ir2110 MOSFETdriver circuit sections, which are combined into separate modules. IR2110 Mosfet, Power supply single working voltage of 65v dc. 800w Class D amplifier project previously shared Class D amplifier having a somewhat complicated design according to the circuit, but the circuit of the landmarks of the calculation formulas ( Class D output filter, power calculations, PWM, etc. ) administration of different does of the source eagle pcb drawing Claas D amplifier projects for It might be useful.
SCHEMATICS CIRCUIT DIAGRAM