# US 2014/0152280 A1 · Apparatus and method for distributing power-up power dissipation

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- Number: US 2014/0152280 A1
- Document ID: US20140152280A1
- Status: Published application
- Kind: A1
- Application number: 14/174,530
- Filed: 2014-02-06
- Published: 2014-06-05
- Earliest claimed: 2011-10-05
- Assignees: Analog Devices, Inc.
- Applicants: Analog Devices, Inc.
- Inventors: George Redfield Spalding, JR.; Marcus O'Sullivan
- Web page: https://patentgrep.com/patent/US20140152280A1

## CPC

- G05F 1/575: characterised by the feedback circuit
- G05F 1/468: {characterised by reference voltage circuitry, e.g. soft start, remote shutdown}
- H03K 17/0822: {in field-effect transistor switches}
- H03K 17/122: {in field-effect transistor switches}
- H03K 3/012: Modifications of generator to improve response time or to decrease power consumption
- H03K 17/687: the devices being field-effect transistors
- H03K 19/00315: {in field-effect transistor circuits}
- H03K 19/017509: {Interface arrangements}
- G05F: SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
- H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M)

## Abstract

A connection device for connecting a load to a power supply, comprising at least first and second current control devices arranged in parallel between the power supply and the load, and a controller arranged to switch the current control devices on in sequence for temporally overlapping on periods.

## Claims

### Claim 1

(canceled)

### Claim 2

A circuit for energizing a load comprising:
a control circuit including:
a first switch control output configured to control a first switch by providing a first control signal varying between establishing a cut-off state and a fully-on-state of the first switch; and
a second switch control output configured to control a second switch by providing a second control signal varying between establishing a cut-off state and a fully-on state of the second switch;
wherein the first and second switch control outputs of the control circuit are configured to respectively provide the first and second control signals to establish a load current to control a rate of change of a voltage across the load to energize the load using the first and second switches in a parallel configuration;
first and second current monitor inputs;
a supply voltage input;
a load voltage input; and
wherein the control circuit is configured to provide a signal at the first switch control output to place the first switch in the fully on state for a first period; to provide a signal at the second switch control output to place the second switch in the cut-off state, to receive a representation of the load current using the first and second current monitor inputs, to receive a representation of a voltage across the first switch using the supply voltage input and the load voltage input, to determine thermal stress information of the first switch using the load current and the representation of the voltage across the first switch, and to modify a length of the first period of the first switch using the thermal stress information.

### Claim 3 (depends on 2)

The control circuit of claim 2, wherein the control circuit is configured to establish an overlapping conduction sequence of the first and second switches.

### Claim 4 (depends on 2)

The control circuit of claim 2, including a feedback circuit configured to monitor the load current provided to the load.

### Claim 5 (depends on 4)

The control circuit of claim 4, wherein the control circuit is configured to use information from the feedback circuit about the monitored load current to establish an intermediate level of conduction between the cut-off state and the fully-on state in the first switch and the second switch to establish the specified load current to control the rate of change of the voltage across the load to energize the load.

### Claim 6 (depends on 5)

The circuit of claim 5, wherein the first and second switch control outputs provided by the control circuit are configured to establish the intermediate level of conduction in the first and second switches to limit the rate of change of the voltage across the load using the information about the monitored load current.

### Claim 7 (depends on 5)

The circuit of claim 5, wherein the first and second switch control outputs provided by the control circuit are configured to provide respective continuously-variable first and second control signals to establish a range of continuously-variable intermediate levels of conduction of the first and second switches to provide the specified load current to control the rate of change of the voltage across the load using the information about the monitored load current.

### Claim 8 (depends on 5)

The circuit of claim 5, wherein the first and second switch control outputs provided by the control circuit are configured to provide the respective first and second control signals to establish a range of discretely-stepped intermediate levels of conduction of the first and second switches to provide the specified load current to control the rate of change of the voltage across the load using the information about the monitored load current.

### Claim 9 (depends on 5)

The circuit of claim 5, wherein the intermediate level of conduction is established in the first switch during a first duration where the first switch is primarily conducting the load current delivered to the load;
wherein the intermediate level of conduction is established in both the first and second switches during a transition duration wherein both the first and second switches are conducting a respective portion of the load current delivered to the load; and
wherein the intermediate level of conduction is established in the second switch during a second duration where the second switch is primarily conducting the load current delivered to the load.

### Claim 10 (depends on 2)

The circuit of claim 2, wherein the first and second switches include Field Effect Transistors (FETs) including respective gate nodes; and
wherein the first and second control signals comprise first and second gate drive signals coupled to first and second gate nodes of the FETs, respectively.

### Claim 11 (depends on 2)

The circuit of claim 2, wherein the first and second switch control outputs provided by the control circuit are configured to establish a monotonically-increasing load voltage using the first and second switches.

### Claim 12 (depends on 2)

The circuit of claim 2, wherein the control circuit is configured to inhibit conduction by the first and second switches using the first and second control outputs when a load current increase persists for longer than a specified duration.

### Claim 13 (depends on 2)

The circuit of claim 2, wherein the control circuit is configured to inhibit any one of the first or second switches from conducting the load current for a duration longer than a specified duration.

### Claim 14

A method for energizing a load comprising:
providing a first signal at a first switch control output to place a first switch in a fully on state for a first period using a first control output of a control circuit
providing a second signal at a second switch control output to place a second switch in a cut-off state using a second control output of the control circuit;
receiving a representation of a load current of the load using first and second current monitor inputs of the control circuit;
receiving a representation of a voltage across the first switch using a supply voltage input of the control circuit and a load voltage input of the control circuit;
determining thermal stress information of the first switch using the load current and the representation of the voltage across the first switch;
modifying a length of the first period of the first switch using the thermal stress information; and
providing first and second switch control signals to establish a specified load current to control a rate of change of a voltage across the load to energize the load using the first and second switches in a parallel configuration.

### Claim 15 (depends on 14)

The method of claim 14, including establishing an overlapping conduction sequence of the first and second switches.

### Claim 16 (depends on 15)

The method of claim 15, including establishing an intermediate level of conduction between the cut-off state and the fully-on state in the first switch and the second switch to establish the specified load current to control the rate of change of the voltage across the load to energize the load.

### Claim 17 (depends on 14)

The method of claim 14, wherein the providing the first and second switch control signals includes establishing the intermediate level of conduction in the first and second switches to limit the rate of change of the voltage across the load using the information about the monitored load current.

### Claim 18 (depends on 14)

The method of claim 14, wherein providing the first and second switch control signals includes providing respective continuously-variable first and second switch control signals to establish a range of continuously-variable intermediate levels of conduction of the first and second switches to provide the specified load current to control the rate of change of the voltage across the load using the information about the monitored load current.

### Claim 19 (depends on 14)

The method of claim 14, wherein providing the first and second switch control signals includes providing respective first and second switch control signals to establish a range of discretely-stepped intermediate levels of conduction of the first and second switches to provide the specified load current to control the rate of change of the voltage across the load using the information about the monitored load current.

### Claim 20 (depends on 14)

The method of claim 14, wherein providing the first and second switch control signals includes establishing a monotonically-increasing load voltage using the first and second switches.

### Claim 21 (depends on 14)

The method of claim 14, comprising, in response to the information about the monitored load current, inhibiting conduction by the first and second switches using the first and second switch control signals when a load current increase persists for longer than a specified duration.

### Claim 22 (depends on 14)

The method of claim 14, comprising, in response to the information about the monitored load current, inhibiting any one of the first or second switches from conducting the load current for a duration longer than a specified duration.

### Claim 23 (depends on 22)

The method of claim 22, wherein inhibiting any one of the first or second switches from conducting the load current includes:
determining the specified duration at least in part using information about a stress on the second switch;
inhibiting the second switch from conducting the load current for a duration longer than the specified duration.