Analysis of Integral Power-on Reset Circuit

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Analysis of Integral Power-on Reset Circuit

Posted Date: 2024-01-17

What are the components of the integral reset circuit?

Integral reset circuit (Integral Reset Circuit) is a reset circuit used in microcontroller systems to restore the system to its initial state during system startup or abnormal conditions. Here are a few common components of an integrating reset circuit:

1. Integrator: It is the core part of the integral reset circuit, usually composed of capacitors and resistors. The integrating circuit converts the pulse signal received from the reset input signal into a continuous reset signal until the system is fully reset.

2. Variable resistor: The variable resistor is used to adjust the integration speed of the integrating circuit. By adjusting the resistance of the variable resistor, the delay time or pulse width of the reset signal can be changed to adapt to different system requirements.

3. Comparator: The comparator is used to compare the output of the integrating circuit with the reference voltage. Through the comparator, it can be detected whether the reset signal has reached the expected state and the system reset can be controlled.

4. Optional additional logic gates: In some cases, logic gates (such as AND gates or OR gates) can be used to further process the reset signal to meet specific reset needs.

5. External power supply: Integral reset circuit usually requires external power supply to ensure its normal operation.

The specific composition of the integrating reset circuit can vary depending on the specific application and needs. Therefore, in an actual design, different components and configurations may be selected to meet specific reset requirements and functionality.

Commonly used power-on or switch reset circuits are shown in the figure. After powering on, RST remains high for a period of time due to the charging of capacitor C3 and the action of the inverting gate. When the microcontroller is already running, pressing the reset key K and then releasing it can also make RST high level for a period of time, thereby realizing the power-on or switch reset operation.

Based on actual operating experience, the reference values ​​of capacitance and resistance of this reset circuit are given below.

In the picture: C:=1uF, Rl=lk, R2=10k

Figure integrated power-on reset circuit

Characteristics of the integral reset circuit

The Integral Reset Circuit has the following characteristics:

1. Long reset time: The integral reset circuit converts the input pulse signal into a continuous reset signal through the integral circuit, so the reset time is relatively long. This ensures that when the system starts, all modules can complete the reset and initialization process to obtain a reliable initial state.

2. Stable reset signal: The integration circuit uses capacitors and resistors to create a delay effect to achieve a stable reset signal. This delay time is relatively stable and is not affected by changes in input pulse width, thus preventing false resets due to short pulses or noise interference.

3. Adjustable reset time: By adjusting the resistance of the variable resistor, the integration speed of the integrating circuit can be changed, thereby adjusting the reset time. This allows the appropriate reset time to be selected based on the needs of the specific application.

4. Independent reset circuit: The integral reset circuit is an independent reset circuit and does not rely on the internal reset function of the microcontroller. This makes the system's reset process more reliable and is not affected by the characteristics and limitations of the microcontroller's internal reset function.

5. Low power consumption: Integral reset circuits usually use capacitors to store energy, so during normal operation, energy consumption is low. This helps reduce system power consumption and extend battery life.

Review Editor: Huang Fei

#Analysis #Integral #Poweron #Reset #Circuit