Linear Technology Corporation

Kirk Su

Jeffrey Lynn Heath

David McLean Dwelley

Ryan Huff

John Arthur Stineman, Jr

Harry Joseph Kleeburg

Clayton Reynolds Stanford

John Stineman

Kaung Zin Htoo

In a method performed by a PoE system, a PSE provides data and operating voltage over Ethernet wires to a PD. Before the full PoE voltage is supplied, the PSE generates a low current signal received by the PD. A circuit in the PD, connected across its input terminals, has a characteristic analog response to the PSE signal corresponding to the PD's PoE requirements, such as whether the PD is a Type 1 or Type 2 PD. The circuit may be a certain value capacitor, zener diode, resistor, or other circuit. The PSE may generate a fixed current, fixed voltage, or time varying signal. Upon the PSE sensing the magnitude of the analog signal response at a particular time, the PSE associates the response with the PoE requirements of the PD. The PSE then applies the full PoE voltage in accordance with the PD's PoE requirements.

Detection and classification scheme for power over Ethernet system

Detection and classification scheme for power over ethernet system

Novel system and methodology for adjusting a current limit threshold in a Power over Ethernet (PoE) system in accordance with requirements of a Powered Device (PD). A system for supplying power to a PD over a communications link has a requirement determining circuit for determining a PD's requirement, and a control circuit for setting a parameter restricting an output signal of the PSE in accordance with the determined PD's requirement. The control circuit may set a current limit threshold of the PSE and/or the PD in accordance with the determined PD's requirement, such as a power requirement.

Adjusting current limit thresholds based on power requirement of powered device in system for providing power over communication link

In a method performed by a Power Over Ethernet (PoE) system, Power Sourcing Equipment (PSE) provides data and voltage over Ethernet wires to a Powered Device (PD). The PD converts the PSE voltage to a regulated voltage by at least one DC-DC converter in the PD. A first load in the PD, such as a processor, operates in a standby mode during a standby period and draws a low current from the converter via a low current path. During this standby period, a high current load in the PD is disconnected and does not draw current. When the first load comes out of the standby mode and into an active mode, the converter supplies a relatively high current to the second load and the first load. In this way, the first load, if a processor, can be already booted up at the time the second load becomes active.

Powered device, using power over ethernet, with dedicated low current and high current paths for loads

In a PoE system in an automobile, Power Source Equipment (PSE) is connected to Powered Devices (PDs) to provide data and power via Ethernet wires. When the ignition switch is on, the full PSE voltage, such as 44 volts, is supplied to the PDs, and the voltage is regulated by the PDs to power one or more loads in the PD. During a standby mode, such as when the ignition switch is off, the PSE is controlled to output a lower voltage of, for example, 5 volts, and the voltage is regulated by the PDs to power the loads, such as processors, in a low power standby mode. The voltage regulator in the PD for the low power mode may be an efficient linear regulator, and the voltage regulator in the PD for the full voltage mode may be a switching regulator. Thus, there is improved efficiency.

Power over ethernet power sourcing equipment provides low voltage output for increased efficiency in low power mode

A Powered Device (PD) in a PoE system has two input channels, each being coupled to a separate Power Sourcing Equipment (PSE) for increased reliability. A first PD controller is coupled to the first channel to perform hand-shaking and closes a first Power Good (PWRGD) switch when the PoE voltage is detected on the first channel. A second PD controller is coupled to the second channel to perform hand-shaking and closes a second PWRGD switch when the PoE voltage is detected on the second channel. A diode bridge couples both channels to a single regulating power supply that supplies power to a load. Auxiliary switches are controlled by the PWRGD signals so that only the first channel or the second channel is coupled to the diode bridge in the event that both channels receive the respective PoE voltages. Therefore, hot standby is provided using only one power supply.

PD in PoE system having redundant PSE channel inputs

Technique for controlling a circuit that converts an AC input voltage into a DC output voltage using transistors arranged in first and second transistor pairs. Each transistor of the first pair is controlled in accordance with polarity of the AC input voltage. Each transistor of the second pair is controlled based on a difference between the AC input voltage and the DC output voltage.

Active bridge rectification

A system for providing power to a load, having first and second power supply inputs respectively responsive to first and second input signals from first and second power supply sources to supply power to the load. For example, the first power supply input may be configured for supplying the load with power received from a communication link, such as an Ethernet link, and the second power supply input may be configured for supplying the load with power from an auxiliary power source. A power converter is provided to produce an output signal for supplying power to the load in response to the second input signal. The power converter is controlled to produce the output signal in accordance with a value of the first input signal.

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Santa Barbara, CA, United States of America

Kirk Su