Current sense circuit topology

A circuit adapted to be coupled between a first current terminal of a high-side transistor of a converter and a second current terminal of the high-side transistor, the circuit comprising:

• a first switch coupled between a first node and a second node;
• a second switch coupled between the first node and a third node, the third node adapted to be coupled to the first current terminal of the high-side transistor;
• a third switch coupled between the second node and the third node;
• a resistor coupled between the second nodes and a fourth node;
• a capacitor coupled between the fourth node and the third node;
• a first transistor comprising a drain terminal coupled to the first node, a source terminal coupled to a fifth node and adapted to be coupled to the second current terminal of the high-side transistor, and a gate terminal coupled to a control terminal of the high-side transistor;
• and
• an amplifier comprising a first input terminal coupled to the fourth node, a second input terminal coupled to the third node, and an output terminal coupled to a sixth node.

A circuit, comprising:

• a high-side transistor comprising a drain terminal coupled to a first node, a source terminal coupled to a second node, and a gate terminal;
• a low-side transistor comprising a drain terminal coupled to the second node;
• and
• a current sense circuit coupled to the first node and the second node and including:
• a high-side replica transistor coupled to the high-side transistor;
• and
• an amplifier having an input connected to the first node through a capacitor;
• wherein the current sense circuit is configured to:
• operate in a first configuration to determine a current flowing through the first high-side transistor based on the replica transistor and generate a signal with a value that is a scaled representation of the current flowing through the high-side transistor;
• and
• operate in a second configuration to determine an average current flowing through the second node and generate a signal with a value that is a scaled representation of the average current flowing through the second node.

A system, comprising:

• a power converter, comprising:
• a first transistor comprising a drain terminal coupled to a first node, a source terminal coupled to a second node, and a gate terminal;
• and
• a second transistor comprising a drain terminal coupled to the second node;
• and
• a current sense circuit coupled to the first node and the second node, and including:
• a high-side replica transistor coupled to the high-side transistor;
• and
• an amplifier having an input connected to the first node through a capacitor:
• wherein the current sense circuit is configured to:
• operate in a first configuration to determine an input current of the power converter based on the replica transistor and generate a signal with a value that is a scaled representation of the input current of the power converter;
• and
• operate in a second configuration to determine an average current flowing through the second node and generate a signal with a value that is a scaled representation of the average current flowing through the second node.