Latching relay control circuitry

Electronic circuits and methods are provided for power conservation applications. A latching relay includes a controlled switch electrically coupled within a power supply of a computer or other load. Circuitry of the present teachings controls operation of the latching relay. Set and reset conditions of the latching relay establish normal and deep standby operating modes for the computer, respectively. Manual switching or automated signaling are used to assert the set and reset relay conditions. Very low power consumption is achieved during the deep standby mode of operation.

BACKGROUND

Numerous desktop computers and other devices are designed to assume one or more types of low power-consumption mode during non-use or other idle periods. Applicable laws and regulations in this area are becoming more stringent as the need to conserve resources is recognized as essential to a sustainable global community. However, many existing power supplies and other circuit designs cannot conform to present or pending power conservation directives. The present teachings address the foregoing concerns.

DETAILED DESCRIPTION

Introduction

Means and methods for conserving power are provided by the present teachings. A latching relay includes a controlled switch that is electrically coupled within a power supply of a computer or other load. Circuitry controls operation of the latching relay. Set and reset conditions of the latching relay correspond to normal and “deep standby” operating modes for the computer, respectively. Manual switching or automated signaling are used to establish set and reset conditions for the latching relay. Very low power consumption is achieved during the deep standby mode of operation.

In one embodiment, an electronic circuit includes a latching relay including a set coil and a reset coil and a switch. The switch has a first end node and a second end node. The electronic circuit also includes a first capacitor electrically coupled to the first end node of the switch. The electronic circuit also includes a second capacitor electrically coupled to the second end node of the switch. The electronic circuitry further includes a rectifier configured to receive electrical current by way of the first and second capacitors. The rectifier is also configured to provide an electrical potential between a first output node and a second output node while the latching relay is in a reset condition.

In another embodiment, a method includes coupling electrical potential between respective end nodes of a switch to a rectifier by way of a pair of capacitors. The switch is in an open state, and the switch is part of a latching relay. The method also includes outputting an electrical potential between a, pair of output nodes of the rectifier. The method also includes coupling electrical current from the pair of output nodes to a set coil of the latching relay. The method further includes closing the switch by way of the set coil.

First Illustrative Embodiment

Reference is now directed toFIG. 1, which depicts a schematic diagram of electronic circuitry100. The circuitry100is illustrative and non-limiting with respect to the present teachings. Thus, other circuits and embodiments can be configured and/or operated in accordance with the present teachings.

The circuitry100includes a rectifier102configured to perform full wave rectification of input alternating-current (AC) electrical power. The rectifier102can be defined by a plurality of discrete diodes, as an integrated rectifier device, or by other suitable means. The rectifier102outputs pulsating direct-current (DC) electrical power between a pair of nodes104and106. The circuitry100also includes a filter capacitor108coupled between the nodes104and106.

The circuitry100further includes a pair of negative temperature coefficient (NTC) thermistors110and112, respectively. Each of the thermistors110and112is configured to limit inrush current to the rectifier102and other elements of the circuitry100. The rectifier102is coupled to a first power input node114, and to a second power input node116by way of the pair of thermistors110and112. The circuitry100also includes a controlled switch (i.e., relay contacts)170that are closed after an inrush current event. The switch170is controlled by a relay of the circuitry that is not shown and is not relevant to an understanding of the present teachings.

It is noted that the rectifier102, the capacitor108, the respective thermistors110and112and the switch170are a part of a switching power supply. One illustrative and non-limiting example of such a power supply is model DPS-1050DB A, available from Delta Electronics, Inc., Fremont, Calif., USA. Circuitry according to the present teachings is discussed hereinafter.

The circuitry100also includes a latching relay100LR having a controllable switch (or pair of contacts)118. In one illustrative embodiment, the latching relay100LR is defined by a model RT314F12, available from Schrack Technik International, Vienna, Austria. Other suitable latching relays can also be used. The switch118is defined by a pair of end nodes120and122. The switch118is controlled so as to be set (i.e., electrically closed) by way of a set coil124, and reset (i.e., electrically opened) by way of a reset coil126, of the latching relay100LR. In this way, the switch118is configured to assume and hold either a set (closed) or reset (open) condition in accordance with the most recently energized coil (set coil124or reset coil126, respectively). Electrical energy within the power supply is directly connected between the end nodes120and122when the switch118is closed.

The circuitry100also includes a resistor128connected to the end node120, and a resistor130connected to the end node122. The circuitry also includes a capacitor132connected to the resistor128, and a capacitor134connected to the resistor130. In this way, the resistors128and130and the capacitors132and134define a pair of respective series-connected electrical circuit paths. The capacitors132and134are also referred to as energy coupling capacitors for purposes herein. In one embodiment, each of the capacitors132and134is defined by a model CD16E2GA472MYNS, available from TDK Corporation of America, Mount Prospect, Ill., USA. Other suitable capacitors can also be used.

The circuitry100includes a rectifier136configured to perform full wave rectification of input alternating-current (AC) electrical power. The rectifier136can be defined by a plurality of discrete diodes, as an integrated rectifier device, or other suitable means. The rectifier136is coupled to receive electrical power from the end nodes120and122of switch118by way of the resistors128-130and the capacitors132-134. The rectifier136is configured to output pulsating direct-current energy between a negative (or ground) node138and a positive node140.

The circuitry100also includes a filter capacitor142and a zener diode144coupled between the respective nodes138and140. The filter capacitor142operates to filter or smooth the pulsating DC electrical output from the rectifier136and provides energy storage necessary to change the latching relay100LR to a set or reset state, while the zener diode144operates to regulate the direct-current voltage between the nodes138and140.

Node140of the circuitry100is connected to a source of fifteen volts direct-current at a node146by way of a steering diode148. Additionally, node140of the circuitry100is connected to a source of five volts direct-current at a node150by way of a zener diode152, which is intended to provide such five volts when the computing system is in the deep standby state. The respective voltages at nodes146and150are typically provided by a power supply (e.g., model DPS-1050DB as cited above, etc.). The ground node138is connected to ground potential.

The set coil124of the latching relay100LR is coupled to receive electrical energy from the positive node140, and ground potential at node138by way of a resistor154and a capacitor156when a normally-open momentary switch158is manually actuated. The switch158is depicted as a normally-open momentary pushbutton type. However, other types of switches or control methods can also be used. Alternatively, the set coil124can receive a ground-potential “WAKE” signal at a node172. A diode160protects the circuitry100against excessive transient voltages induced in the set coil124during opening of the switch158.

The reset coil126of the latching relay100LR is coupled to receive electrical energy from the positive node140, and ground potential at node138by way of a resistor162and a capacitor164when a normally-open momentary switch166is manually actuated. The switch166is depicted as a normally-open momentary pushbutton type. However, other types of switches or control methods can also be used. In the alternative, the reset coil126can receive a ground-potential “DEEP STANDBY” signal at a node174. A diode168protects the circuitry100against excessive transient voltages induced in the reset coil126during opening of the switch166.

Relay contacts170are part of an inrush current-control relay of the circuitry100and are configured to electrically short around the thermistors110and112and the switch118when the power supply is enabled to output power to all loads, which occurs during power supply startup.

Normal operations of the circuitry100are described hereinafter. Table 1 below provides illustrative and non-limiting values for elements and components of the circuitry100that are germane to the present teachings:

FIG. 2is a flow diagram depicting a method according to tone embodiment of the present teachings. The method ofFIG. 2includes particular operations and order of execution. However, other methods including other operations, omitting one or more of the depicted operations, and/or proceeding in other orders of execution can also be used according to the present teachings. Thus, the method ofFIG. 2is illustrative and non-limiting in nature. Reference is also made toFIG. 1in the interest of understanding the method ofFIG. 2.

At200, a “DEEP STANDBY” signal is asserted by way of a user momentarily pressing a “deep standby” pushbutton, or by the automatic issuance of a deep standby signal. This signal is provided so as to place a computer or other load device into a deep standby, power-conserving mode of operation. For purposes of illustration and test, it is understood that a user presses the deep standby pushbutton switch166of the circuitry100.

At202, direct-current electricity from at least one power buss flows through the reset coil of a latching relay. For purposes of the ongoing example, fifteen volts electrical energy at node146, which is provided by an operating power supply, is coupled such that electrical current flows through the reset coil126by way of node140and switch166.

At204, the latching relay assumes a reset condition as a result of the steps200and202above. For purposes of example, the controlled switch118of the latching relay100LR assumes an electrically open or “reset” condition. The open condition of the switch118is maintained until such time as a normal “set” operation is performed.

At206, the power supply is de-energized. For purposes of example, it is understood that the power supply is de-energized (source power is effectively removed) as a result of the opening of the switch118of the latching relay100LR, and by independent control of relay contacts170of the inrush current control relay of circuitry100.

At208, a computer or other load device assumes a deep standby condition. For purposes of the example, it is understood that the de-energized power supply results in minimal power consumption by the computer (or other load).

The foregoing method is illustrative of any number of methods contemplated by the present teachings. In general, and without limitation, a user presses a pushbutton or otherwise actuates a manual switch, or a deep standby signal is asserted by a computer or other device. Electrical current from an operating power supply is coupled by circuitry to a reset coil of a latching relay, resulting in the opening of controlled electrical contacts. Electrical power is thus disconnected within the power supply circuitry and the power supply is effectively shut down. A computer or other load that receives electrical power from the power supply is placed in a deep standby, power conservation mode of operation.

It is noted that the inrush relay switch170effectively shorts out the switch118during normal, full-power operation. As a result, the latching relay100LR can be reset for deep standby operations while the switch170is electrically closed without affecting normal operations of a computer or other load device. Under such a scenario, the computer (or other load) can assume some other power conservation state (e.g., S4 or S5 “sleep” mode, etc.) and the latching relay100LR will already be in a reset condition.

Second Illustrative Method

FIG. 3is a flow diagram depicting a method according to one embodiment of the present teachings. The method ofFIG. 3includes particular operations and order of execution. However, other methods including other operations, omitting one or more of the depicted operations, and/or proceeding in other orders of execution can also be used according to the present teachings. Thus, the method ofFIG. 3is illustrative and non-limiting in nature. Reference is also made toFIG. 1in the interest of understanding the method ofFIG. 3.

At300, a “WAKE signal is asserted by way of a user momentarily pressing a wake” pushbutton, or by the automatic issuance of a “wake” signal. This signal is provided so as to return a computer (or other load device) from a deep standby mode to a state of normal operations. For purposes of non-limiting illustration, it is understood that a user presses the “wake” pushbutton switch158of the circuitry100.

At302, rectified electricity from a line (i.e., utility) source is coupled to flow through the set coil of a latching relay. For purposes of the ongoing example, it is understood that electrical potential between end nodes120and122of the switch118(which is in an open condition) is coupled to the set coil124of the circuit100by way of node140. Resistors128-130, capacitors132-134and rectifier136define a part of the circuit path that provides the electrical current to the set coil124.

At304, the latching relay assumes a set condition as a result of the steps300and302above. For purposes of example, the controlled switch118of the latching relay100LR assumes an electrically closed or “set” state, followed thereafter by a closed condition of the switch170(under independent control). The closed condition of the switch118is maintained until such time as a normal “reset” operation is performed.

At306, the power supply is re-energized. For purposes of example, it is understood that a power supply is re-coupled to line power as a result of the closing of the switch118of the latching relay100LR.

At308, a computer or other load device assumes a normal operating condition. For purposes of the example, it is understood that the re-energized power supply results in normal operation by the computer (or other load).

The foregoing method is illustrative of any number of methods contemplated by the present teachings. In general, and without limitation, a user presses a pushbutton or otherwise actuates a manual switch, or a wake signal is asserted by a computer or other device. Electrical current from line sources is coupled by circuitry to a set coil of a latching relay, resulting in the closing of controlled electrical contacts. Electrical source power is thus coupled within the power supply circuitry, and the power supply resumes normal operation. In turn, a computer or other load receives full electrical power from the power supply and normal computing (or other) operations can resume. A switch activated by a user can be placed on a front panel or other convenient location of the computer (or other entity).

First Illustrative System

FIG. 4is block diagram depicting a computer400according to an illustrative and non-limiting embodiment of the present teachings. Numerous other embodiments are contemplated that incorporate the present teachings.

The computer400includes a power supply402. The power supply402can be defined by any suitable power supply consistent with the present teachings. In one non-limiting embodiment, the power supply402is as defined above with respect toFIG. 1. Other power supplies can also be used. The power supply402includes, or is electrically coupled to, circuitry404according to the present teachings. The circuitry404can be defined by the circuitry100as described above. The circuitry404includes a latching relay406that is controlled by other features of the circuitry404.

The computer400also includes at least one processor408, memory410and power management circuitry412. The processor408and memory410are respectively defined as known in the art, and one having ordinary skill in computers and the related arts can appreciate that no further elaboration is needed for an understanding of the present teachings. The power management circuitry412is configured to provide one or more signals (e.g., “deep standby”, “wake”, etc.) and operates to control power conservation within the computer400.

The computer400also includes other resources414. Non-limiting examples of such other resources414include mass storage, a display or monitor, a keyboard, a mouse, network communications circuitry, etc. One having ordinary skill in the computing arts can appreciate that numerous resources can be included as needed or desired, and that further elaboration is not required for an understanding of the present teachings. The computer400is coupled to a line power source (i.e., utility power)416.

Normal illustrative and non-limiting operations of the computer400are as follows: the computer400operates by way of electrical energy provided by power supply402. Eventually, it is desired for the computer400to enter a power conserving deep standby operating mode. At such time, the power management circuitry412issues a deep standby signal to circuitry404. Such a deep standby signal can, for example, be a ground-potential signal provided at a node174of circuitry100.

In response to the deep standby signal, the circuitry404causes a reset (or open switch) condition of the latching relay406. In turn, the open contacts of the latching relay406enables a de-energized state of the power supply402. As an overall result, electrical power is no longer provided from the power supply402to the balance of the computer400. However, the power management circuitry is assumed to stay energized during deep standby by way of a battery power source, a micro-wattage power supply, or other electrical source (not shown).

At some future time, it is desired for the computer to return to a normal operating state. Thus, a wake signal is issued from the power management circuitry412to the circuitry404. Such a wake signal can, for example, be a ground-potential signal provided at a node172of circuitry100.

In response to the wake signal, the circuitry404causes a set (or closed switch) condition of the latching relay406. The closed contacts of the latching relay406allows the power supply402to return to a fully operational state. As a result, electrical power is once again enabled from the power supply402to the balance of the computer400. The computer400can now be operated and used as normal.