Improve power supply rejection ratio PSR circuit diagram ISO124

Description: The circuit depicted in the figure includes the ISO124 and MC78L05 components, along with an external regulator, MC79L05, and the DCP011515, which collectively enhance the power supply rejection ratio (PSR) of the circuit. The input signal, VIN (maximum swing of 10V), is processed through the ISO124 for isolation. The isolated DC/DC converter, DCP011515, is responsible for supplying isolated power, and two three-terminal integrated voltage regulators, MC78L05 and MC79L05, are incorporated between the DCP011515 and ISO124. The MC78L05, a Motorola product, provides a +5V output at 100mA, while the MC79L05 delivers a -5V output at 100mA. These regulators serve as auxiliary devices, allowing for the adjustment of the power supply rejection ratio error without compromising the 10V input range.

The circuit is designed to optimize the power supply rejection ratio (PSR) by utilizing a combination of isolation and regulation techniques. The ISO124 is a precision instrumentation amplifier that provides electrical isolation between the input and output, ensuring that any noise present in the ground reference does not affect the signal integrity. The DCP011515 is a highly efficient isolated DC/DC converter that steps down the voltage while maintaining isolation, which is crucial for sensitive applications where ground loops may introduce errors.

The integration of the MC78L05 and MC79L05 voltage regulators enhances the circuit's performance by providing stable output voltages of +5V and -5V, respectively. These regulators are designed to work effectively with the DCP011515's output, ensuring that the isolated power supply remains stable under varying load conditions. The use of these auxiliary regulators helps to minimize the PSR error, thus improving the overall reliability of the power supply system.

In this configuration, the input voltage (VIN) can swing up to 10V, and the regulators are capable of maintaining their output specifications within this range. The MC78L05 and MC79L05 are specifically chosen for their low dropout voltage and high output current capabilities, making them suitable for applications that require precise voltage regulation with minimal noise. This circuit is particularly beneficial in environments where power supply variations can lead to significant performance degradation in sensitive electronic systems. As shown in FIG grounds ISO124 and MC78L05, an external regulator MC79L05 and DCP011515 constituted improve power supply rejection ratio (PSR) circuit. Input signal VIN (maximu m swing 10V) output by the isolation after ISO124. Isolated DC/DC DCP011515 change is responsible for providing isolated power supply, and in between DCP011515 and ISO124 added two three-terminal integrated power supply MC78L05 and MC79L05. MC78L05 and MC79L05 is Motorola products, MC78L05 output + 5V, 100mA, MC79L05 output -5V, 100mA. Use MC78L05 and MC79L05 as an auxiliary regulator adjusted so without reducing the 10V input range conditions can reduce power-supply rejection ratio error.