Power-on reset circuit

A power-on reset circuit for providing a power-on reset signal when a power supply voltage reaches a threshold voltage, the power-on reset circuit comprising:

• a first branch configured to receive the power supply voltage, the first branch comprising a first current generator configured to generate a first current having a positive relationship with the power supply voltage;
• a second branch configured to receive the power supply voltage, the second branch comprising a second current generator configured to generate a second current, a relationship between the first and second currents indicating whether the power supply voltage exceeds the threshold voltage;
• a current comparator circuit configured to
• compare the first current to the second current, and
• generate an output signal based on the comparison, the power-on reset signal being asserted when the output signal indicates that the second current is greater than the first current;
• a resistor having first and second nodes, the first node being connected to the power supply voltage;
• a capacitor coupled between the second node of the resistor and a ground reference voltage;
• and
• a feedback network coupled to the second node of the resistor, the feedback network being configured to receive the output of the current comparator circuit and to draw a first feedback current from the power supply voltage when the output indicates that the first current is greater than the second current and to draw a second feedback current from the power supply voltage when the output indicates that the second current is greater than the first current.

A power-on reset circuit for providing a power-on reset signal when a power supply voltage reaches a threshold voltage, the power-on reset circuit comprising:

• a first branch configured to receive the power supply voltage, the first branch comprising a first current generator configured to generate a first current, the first branch including a resistance circuit coupled between the first current generator and a ground reference voltage, wherein the resistance circuit comprises,
• a voltage divider having a first node connected to the first current generator and a second node connected to the ground reference voltage, the voltage divider comprising (i) a first resistor coupled between the first node and an intermediate node, and (ii) a second resistor coupled between the intermediate node and the ground reference voltage;
• a second branch configured to receive the power supply voltage, the second branch comprising a second current generator coupled to the intermediate node of the voltage divider and configured to generate a second current, a relationship between the first and second currents indicating whether the power supply voltage exceeds the threshold voltage;
• a current comparator circuit configured to
• compare the first current to the second current, and
• generate an output based on the comparison, the power-on reset signal being asserted when the output indicates that the second current is greater than the first current;
• and
• a feedback network configured to receive the output of the current comparator and draw a current from the power supply voltage, an amount of the current drawn varying based on the output.

A power-on reset circuit for providing a power-on reset signal when a power supply voltage reaches a threshold voltage, the power-on reset circuit comprising:

• a first branch configured to receive the power supply voltage, the first branch comprising a first current generator configured to generate a first current;
• a second branch configured to receive the power supply voltage, the second branch comprising a second current generator configured to generate a second current, a relationship between the first and second currents indicating whether the power supply voltage exceeds the threshold voltage;
• a current comparator circuit configured to
• compare the first current to the second current, and
• generate an output based on the comparison, the power-on reset signal being asserted when the output indicates that the second current is greater than the first current;
• a feedback network configured to receive the output of the current comparator and draw a current from the power supply voltage, an amount of the current drawn varying based on the output;
• a resistor having first and second nodes, the first node being connected to the power supply voltage;
• and
• a capacitor coupled between the second node of the resistor and a ground reference voltage, wherein the feedback network is coupled to the second node of the resistor and is configured to (i) draw a first feedback current from the power supply voltage when the output indicates that the first current is greater than the second current, and (ii) draw a second feedback current from the power supply voltage when the output indicates that the second current is greater than the first current.