DC-DC converter with switching noise suppression circuitry
A DC-DC converter is disclosed. The DC-DC converter includes a sensing circuit having a first path to sense an output current of the DC/DC converter. A reference circuit generates a reference current to flow along a second path. The reference current is for comparison to the output current. A noise injection circuit couples to the second path and includes a replica circuit of the sensing circuit to sense the reference current. A differential amplifier rejects a common mode noise between the first path and the second path.
1 . A DC/DC converter, comprising:
a sensing circuit comprising active current measurement circuitry to sense an output current of the DC/DC converter;
a reference circuit to generate a reference current to flow along a second path, the reference current for comparison to the output current;
a noise injection circuit coupled to the second path and comprising a replica circuit of the sensing circuit to sense the reference current, the replica circuit comprises replica current measurement circuitry; and
a differential amplifier to reject a common mode noise between the first path and the second path, the common mode noise comprising a switching noise component.
2 . The DC/DC converter of claim 1 , further comprising:
switching regulator circuitry to generate the output current as a switching current.
3 . The DC/DC converter of claim 1 , further comprising:
overcurrent protection circuitry to monitor the output current and to disable the DC/DC converter based on an output from the differential amplifier.
4 . The DC/DC converter of claim 3 , wherein:
the overcurrent protection circuitry comprises comparator circuitry to compare the output from the differential amplifier to a threshold overcurrent value.
5 . The DC/DC converter of claim 1 , realized as a power management integrated circuit (PMIC) chip.
6 . An integrated circuit (IC) chip, comprising:
a switching circuit to generate output current pulses for an off-chip power smoothing circuit;
a first sensing circuit comprising an active noise measurement circuit to generate a first sensing signal during a switch interval, the first sensing signal based on a sensed output current of the switching circuit and comprising a first noise component;
a second sensing circuit comprising a replica active current measurement circuit to sense a reference current from a reference current path and to generate a second sensing signal based on the switched reference current during the switch interval, the second sensing signal comprising a second noise component; and
a differential amplifier circuit to receive the first sensing signal and the second sensing signal and to reject the first noise component and the second noise component as common mode noise between the first sensing signal and the second sensing signal, wherein the common mode noise comprises switching noise common to the first noise component and the second noise component.
7 . The IC chip of claim 6 , further comprising:
overcurrent protection circuitry to monitor the output current pulses and to disable the DC/DC converter based on an output from the differential amplifier.
8 . The IC chip of claim 7 , wherein:
the overcurrent protection circuitry comprises comparator circuitry to compare the output from the differential amplifier to a threshold overcurrent value.
9 . The IC chip of claim 6 , realized as a power management integrated circuit (PMIC) chip.
10 . The IC chip of claim 6 , wherein:
the switching circuit is to generate the output current pulses for a dynamic random access memory (DRAM) power smoothing circuit.
11 . A method of operation in a DC-DC converter, the method comprising:
sensing an output current of the DC-DC converter with a sensing circuit via a first path;
flowing a reference current via a second path, the reference current for comparison to the output current;
generating replica noise with a replica sensing circuit;
injecting the replica noise into the second path; and
canceling a power supply coupling noise common to the first path and the second path with a differential amplifier.
12 . The method of claim 11 , wherein the canceling comprises:
canceling a switching noise common to the first path and the second path.
13 . The method of claim 11 , further comprising:
monitoring the output current; and
disabling the DC/DC converter based on an output of the differential amplifier.
14 . The method of claim 13 , further comprising:
comparing the output of the differential amplifier to a threshold overcurrent value to generate a comparison; and
disabling the DC/DC converter based on the comparison.
15 . The method of claim 11 , further comprising:
operating the DC/DC converter to provide a regulated power supply to memory devices disposed on a memory module.