Combined high side and low side current sensing

A current sensing circuit for a high side current through a high side switch and/or for a low side current through a low side switch of a half bridge comprising the high side switch and the low side switch, which are arranged in series between a high side potential and a low side potential;

• wherein the high side switch and the low side switch are controlled to be in respective on-phases in a mutually exclusive manner;
• wherein the current sensing circuit comprises,
• a high side sensing circuit configured to provide a sensed high side current which is indicative of the high side current during an on-phase of the high side switch;
• and
• a low side sensing circuit configured to provide a sensed low side current which is indicative of the low side current during an on-phase of the low side switch;
• wherein the low side sensing circuit comprises mirroring circuitry which is configured to mirror a current from a first node of the low side sensing circuit to an output node of the low side sensing circuit;
• wherein the sensed low side current is provided at the output node;
• wherein the sensed high side current is fed to the first node, such that the current at the output node is indicative of the sensed high side current during the on-phase of the high side switch;
• wherein, during the on-phase of the low side switch, the mirroring circuitry is configured to transform a voltage drop across the low side switch into the sensed low side current at the output node.

A switched mode power converter, wherein the power converter comprises,

• a high side switch and a low side switch, which are arranged in series between a high side potential and a low side potential and which form a half bridge;
• a current sensing circuit for a high side current through a high side switch and/or for a low side current through a low side switch of a half bridge comprising the high side switch and the low side switch, which are arranged in series between a high side potential and a low side potential;
• wherein the high side switch and the low side switch are in respective on-phases in a mutually exclusive manner;
• wherein the current sensing circuit comprises,
• a high side sensing circuit configured to provide a sensed high side current which is indicative of the high side current during an on-phase of the high side switch;
• wherein the high side sensing circuit comprises mirroring circuitry which is configured to mirror a current from a first node of the high side sensing circuit to an output node of the high side sensing circuit;
• wherein the sensed high side current is provided at the output node;
• and
• a low side sensing circuit configured to provide a sensed low side current which is indicative of the low side current during an on-phase of the low side switch, wherein the sensed low side current is fed to the first node, such that the current at the output node is indicative of the sensed low side current during the on-phase of the low side switch;
• wherein, during the on-phase of the high side switch, the mirroring circuitry is configured to transform a voltage drop across the high side switch into the sensed high side current at the output node;
• and
• a control unit which is configured to put the high side switch and the low side switch in respective on-phases in a mutually exclusive manner, based on the sensed high side current and/or the sensed low side current.

A method for sensing a high side current through a high side switch and/or for sensing a low side current through a low side switch of a half bridge comprising the high side switch and the low side switch, which are arranged in series between a high side potential and a low side potential;

• wherein the high side switch and the low side switch are controlled to be in respective on-phases in a mutually exclusive manner;
• wherein the method comprises,
• providing a sensed high side current which is indicative of the high side current during an on-phase of the high side switch using a high side sensing circuit;
• wherein the high side sensing circuit comprises mirroring circuitry to mirror a current from a first node of the high side sensing circuit to an output node of the high side sensing circuit;
• wherein the sensed high side current is provided at the output node;
• and
• providing a sensed low side current which is indicative of the low side current during an on-phase of the low side switch using a low side sensing circuit;
• and
• feeding the sensed low side current to the first node, such that the current at the output node is indicative of the sensed low side current during the on-phase of the low side switch;
• wherein, during the on-phase of the high side switch, a voltage drop across the high side switch is transformed into the sensed high side current at the output node using the mirroring circuitry.

A method for sensing a high side current through a high side switch and/or for sensing a low side current through a low side switch of a half bridge comprising the high side switch and the low side switch, which are arranged in series between a high side potential and a low side potential;

• wherein the high side switch and the low side switch are controlled to be in respective on-phases in a mutually exclusive manner;
• wherein the method comprises,
• providing a sensed high side current which is indicative of the high side current during an on-phase of the high side switch using a high side sensing circuit;
• and
• providing a sensed low side current which is indicative of the low side current during an on-phase of the low side switch using a low side sensing circuit;
• wherein the low side sensing circuit comprises mirroring circuitry to mirror a current from a first node of the low side sensing circuit to an output node of the low side sensing circuit;
• wherein the sensed low side current is provided at the output node;
• and
• feeding the sensed high side current to the first node, such that the current at the output node is indicative of the sensed high side current during the on-phase of the low side switch;
• wherein, during the on-phase of the low side switch, a voltage drop across the low side switch is transformed into the sensed low side current at the output node using the mirroring circuitry.

A switched mode power converter, wherein the power converter comprises,

• a high side switch and a low side switch, which are arranged in series between a high side potential and a low side potential and which form a half bridge;
• a current sensing circuit for a high side current through a high side switch and/or for a low side current through a low side switch of a half bridge comprising the high side switch and the low side switch, which are arranged in series between a high side potential and a low side potential;
• wherein the high side switch and the low side switch are controlled to be in respective on-phases in a mutually exclusive manner;
• wherein the current sensing circuit comprises,
• a high side sensing circuit configured to provide a sensed high side current which is indicative of the high side current during an on-phase of the high side switch;
• and
• a low side sensing circuit configured to provide a sensed low side current which is indicative of the low side current during an on-phase of the low side switch;
• wherein the low side sensing circuit comprises mirroring circuitry which is configured to mirror a current from a first node of the low side sensing circuit to an output node of the low side sensing circuit;
• wherein the sensed low side current is provided at the output node;
• wherein the sensed high side current is fed to the first node, such that the current at the output node is indicative of the sensed high side current during the on-phase of the high side switch;
• wherein, during the on-phase of the low side switch, the mirroring circuitry is configured to transform a voltage drop across the low side switch into the sensed low side current at the output node;
• and
• a control unit which is configured to put the high side switch and the low side switch in respective on-phases in a mutually exclusive manner, based on the sensed high side current and/or the sensed low side current.