US-20260128583-A1 - POWER SUPPLY DEVICE

US20260128583A1US 20260128583 A1US20260128583 A1US 20260128583A1US-20260128583-A1

Abstract

A power supply device includes: a power device that supplies current from a driving power source to a load; an off-chip detection resistor through which another current based on the current is energized; a data converter that converts a voltage converted by the off-chip detection resistor into a data value based on a predetermined characteristic; a protection operation unit that performs a protection operation to stop the power device from supplying the current to the load when a calculation value based on the data value exceeds a threshold value; and an IC chip on which the data converter and the protection operation unit are mounted. The IC chip has a configuration capable of switching a voltage level obtained with respect to another current based on the current in a plurality of stages.

Inventors

Naoto Yokoyama

Assignees

DENSO CORPORATION

Dates

Publication Date: 20260507
Application Date: 20251219
Priority Date: 20230629

Claims (15)

1 . A power supply device comprising: a power device that supplies current from a driving power source to a load; an off-chip detection resistor through which another current based on the current is energized; a data converter that converts a voltage converted by the off-chip detection resistor into a data value based on a predetermined characteristic; a protection operation unit that performs a protection operation to stop the power device from supplying the current to the load when a calculation value based on the data value exceeds a threshold value; and an IC chip on which the data converter and the protection operation unit are mounted, wherein: the IC chip has a configuration capable of switching a voltage level obtained with respect to another current based on the current in a plurality of stages.
2 . The power supply device according to claim 1 , further comprising: a gain switching unit that switches the voltage level obtained by switching a gain with respect to another current based on the current, wherein: the data converter performs data conversion in a state where the gain is set to a minimum value; and the gain for detecting the current is determined according to a converted data value.
3 . The power supply device according to claim 1 , further comprising: a source-side current supply source that energizes the off-chip detection resistor in a state where the power device stops energizing the load, wherein: an anomaly in a connection state of the off-chip detection resistor is determined in accordance with a data value converted when energizing.
4 . The power supply device according to claim 3 , further comprising: a correction unit that corrects an output data of the data converter, wherein: when an anomaly of the detection resistor is detected, a correction parameter of the correction unit is set so that the protection operation unit starts performing the protection operation more quickly.
5 . The power supply device according to claim 3 , wherein: when an anomaly of the detection resistor is detected, an input voltage of the data converter is set to be higher than a normal input range.
6 . The power supply device according to claim 1 , further comprising: a source-side current supply source that energizes the off-chip detection resistor in a state where the power device stops energizing the load; and a control unit that determines a resistance value of the off-chip detection resistor based on a result of data conversion associated with energization, and sets a control parameter according to a determined resistance value.
7 . The power supply device according to claim 1 , wherein: the IC chip includes a resistance value changing unit that has a plurality of on-chip detection resistors connectable in parallel to the off-chip detection resistor; the data converter performs data conversion in a state where a combined resistance value of the off-chip detection resistor and the on-chip detection resistor is in a minimum state; and the combined resistance value for detecting the current is determined according to a converted data value.
8 . The power supply device according to claim 1 , further comprising: a source-side current supply unit that energizes the off-chip detection resistor in a state where the power device stops energizing the load, wherein: a resistance value of a on-chip detection resistor is corrected according to a data value converted when the off-chip detection resistor is energized by a source side current supply.
9 . The power supply device according to claim 8 , further comprising: a correction unit that corrects an output data of the data converter, wherein: when an anomaly of the detection resistor is detected, a correction parameter of the correction unit is set so that the protection operation unit starts performing the protection operation more quickly.
10 . The power supply device according to claim 8 , wherein: when an anomaly of the detection resistor is detected, an input voltage of the data converter is set to be higher than a normal input range.
11 . The power supply device according to claim 1 , further comprising: another power device that supplies another current from the driving power source (VB) to the off-chip detection resistor, wherein: the power device and another power device constitute an IPD; a drain of the power device and a drain of another power device are connected to the driving power source; a gate of the power device and a gate of another power device are commonly connected to each other; a source of the power device is connected to the load via a wire harness; a source of another power device is connected to a ground via the off-chip detection resistor; the data converter is an A/D converter; an input terminal of the A/D converter is connected to a common connection point between another power device and the off-chip detection resistor; an output terminal of the A/D converter is connected to the protection operation unit; and the protection operation unit drives the gate of the power device and a gate of another power device.
12 . The power supply device according to claim 11 , wherein: the protection operation unit includes an eFuse (I 2 , t) characteristic calculation unit, a cut-off determination unit, and an output control unit; the data value of the A/D converter is input to the eFuse (I 2 , t) characteristic calculation unit; a calculation result of the eFuse (I 2 , t) characteristic calculation unit is input to the cut-off determination unit; a determination result of the cut-off determination unit is input to the output control unit; the eFuse (I 2 , t) characteristic calculation unit calculates the calculation result based on the data input from the A/D converter according to a feature that a smoke generation time of the wire harness depends on a square of the current to be energized; the cut-off determination unit determines as the determination result whether or not to issue a cut-off instruction by comparing the calculation result of the eFuse (I 2 , t) characteristic calculation unit with a threshold value; and the output control unit turns off the power device and another power device in response to an input of the cut-off instruction from the cut-off determination unit.
13 . The power supply device according to claim 12 , wherein: the configuration of the IC chip capable of switching the voltage level obtained with respect to another current is provided by a gain switching unit that switches the voltage level obtained by switching a gain with respect to another current; the gain switching unit is connected between the input terminal of the A/D converter and the off-chip detection resistor; the gain switching unit allows the gain to be switched between two or more stages; and a gain switching control of the gain switching unit is performed by the eFuse (I 2 , t) characteristic calculation unit.
14 . The power supply device according to claim 13 , wherein: the gain switching unit selects a gain that can ensure a highest resolution within a range of voltages that can be input to the A/D converter to virtually improve a resolution of data conversion in the A/D converter and to improve an accuracy of current detection in a small current region where the accuracy is most required and in a vicinity of an upper limit current that can steadily flow through the wire harness.
15 . The power supply device according to claim 12 , wherein: the configuration of the IC chip capable of switching the voltage level obtained with respect to another current is provided by a resistance value changing unit that has a plurality of on-chip detection resistors connectable in parallel to the off-chip detection resistor; the data converter performs data conversion in a state where a combined resistance value of the off-chip detection resistor and the on-chip detection resistor is in a minimum state; the combined resistance value for detecting the current is determined according to a converted data value; and the resistance value changing unit changes the combined resistance value with the off-chip detection resistor and reduces a voltage input to the A/D converter to virtually improve a resolution of the data conversion in the A/D converter and to improve an accuracy of current detection in a small current region where the accuracy is most required and in a vicinity of an upper limit current that can steadily flow through the wire harness.

Description

CROSS REFERENCE TO RELATED APPLICATION The present application is a continuation application of International Patent Application No. PCT/JP2024/020200 filed on Jun. 3, 2024, which designated the U.S. and claims the benefit of priority from Japanese Patent Application No. 2023-107121 filed on Jun. 29, 2023. The entire disclosures of all of the above applications are incorporated herein by reference. TECHNICAL FIELD The present disclosure relates to a power supply device including a power device that supplies a current from a driving power source to a load. BACKGROUND For example, a conceivable technique teaches a method of implementing a fuse function using a semiconductor switch to protect a wire harness and a load. Hereinafter, such a protection function may be referred to as eFuse control. To achieve the eFuse control, it is necessary to cut off the current quickly when a large current flows due to the thermal time constant of the wire harness. On the other hand, in order to reduce costs by making the harness thinner, it is necessary to improve the accuracy of current detection near the limit current that can be steadily passed through the harness. SUMMARY According to an example, a power supply device may include: a power device that supplies current from a driving power source to a load; an off-chip detection resistor through which another current based on the current is energized; a data converter that converts a voltage converted by the off-chip detection resistor into a data value based on a predetermined characteristic; a protection operation unit that performs a protection operation to stop the power device from supplying the current to the load when a calculation value based on the data value exceeds a threshold value; and an IC chip on which the data converter and the protection operation unit are mounted. The IC chip has a configuration capable of switching a voltage level obtained with respect to another current based on the current in a plurality of stages. BRIEF DESCRIPTION OF THE DRAWINGS The above and other features and advantages of the present disclosure will become more apparent from the following detailed description made with reference to the accompanying drawings. In the drawing: FIG. 1 is a diagram showing a configuration of a power supply device according to a first embodiment; FIG. 2 is a diagram showing the relationship between a load current and an A/D conversion value when the resistance value of an I/V conversion resistor is only a low resistance; FIG. 3 is a diagram showing the relationship between a load current and an A/D conversion value when the resistance value of an I/V conversion resistor is capable of switching between a low resistance and a high resistance; FIG. 4 is a diagram (first part) showing a configuration of a gain switching unit; FIG. 5 is a diagram (second part) showing a configuration of a gain switching unit; FIG. 6 is a diagram (third part) showing a configuration of a gain switching unit; FIG. 7 is a diagram showing the relationship between a load current and an A/D conversion value when the gain is switched; FIG. 8 is a flowchart illustrating a procedure of a process in a control unit according to a second embodiment; FIG. 9 is a diagram (first part) showing a configuration of a power supply device according to a third embodiment; FIG. 10 is a diagram (second part) showing a configuration of a power supply device; FIG. 11 is a diagram showing a configuration of a power supply device according to a fourth embodiment; FIG. 12 is a flowchart illustrating a procedure of a process in a control unit according to a fifth embodiment, a twelfth embodiment or a thirteenth embodiment; FIG. 13 is a flowchart illustrating a procedure of a process in a control unit according to a sixth embodiment or a fourteenth embodiment; FIG. 14 is a diagram showing an example of a table used to determine the type of IPD; FIG. 15 is a flowchart illustrating a procedure of a process in a control unit according to a seventh embodiment or a fifteenth embodiment; FIG. 16 is a diagram for explaining a process of correcting an A/D conversion result by applying a linear function; FIG. 17 is a diagram showing a configuration of a power supply device according to an eighth embodiment; FIG. 18 is a flowchart showing a procedure of a process in a control unit; FIG. 19 is a diagram showing a configuration of a power supply device according to an ninth embodiment; FIG. 20 is a diagram showing a combined resistance value in the chip given according to the on/off states of the switches SW1 to SW4; FIG. 21 is a diagram showing a relationship between a load current and an A/D conversion value when a combined resistance value of an off-chip detection resistor and an on-chip detection resistor is switched; FIG. 22 is a diagram showing a configuration of a power supply device according to a tenth embodiment; FIG. 23 is a diagram showing a combined resistance value in the chip given according to the o