| Specialized | 2 | NRND | |
TPS2371Legacy/IEEE802.3af Compatible Power Interface Switch for PoE PDs | Interface | 1 | NRND | Acting as an interface between the Power Source Equipment (PSE) and the Powered Device (PD), the TPS2371 performs all detection, classification, inrush current limiting, and switch FET control that is necessary for compatibility with Legacy/IEEE 802.3af Standard. The TPS2371 incorporates precision UVLO thresholds and hysteresis as well as a UVLO off-time delay to enable Legacy IEEE802.3af PoE compatibilty. An internal 0.3-FET provides maximum power delivery. As an additional feature, the TPS2371 interfaces with the enable/soft-start signal of a dc-to-dc converter, eliminating the need to have an accurate UVLO in the dc-to-dc converter.
At low input voltages (1.8 V to 10 V), the TPS2371 draws less than 12 µA, allowing accurate sensing of the external 24.9-kdiscovery resistor. At input voltages between 15 V and 20 V, an external resistor sets the level of current to be drawn during classification mode. TPS2371 is compatible with current as well as voltage measurement schemes for classification. Above 20-V input, the classification current is shut off, reducing internal power dissipation.
The TPS2371 drives an internal low-side FET for control of the return side of the power path. The internal FET is turned on when the input voltage reaches 36 V and above. When the input voltage decreases, the FET remains on until the input voltage drops to below 30 V.
During initial turn-on of the switch (inrush mode), an external resistor is used to program the inrush current, allowing a wide range of capacitor values to be used at the load. According to IEEE 802.3af specification, inrush current of 400 mA is allowed only for 50 ms, limiting the load capacitor to approximately 180 µF. A programmable inrush current limit removes this limitation, allowing a larger capacitor to be used with a lower inrush current limit.
Acting as an interface between the Power Source Equipment (PSE) and the Powered Device (PD), the TPS2371 performs all detection, classification, inrush current limiting, and switch FET control that is necessary for compatibility with Legacy/IEEE 802.3af Standard. The TPS2371 incorporates precision UVLO thresholds and hysteresis as well as a UVLO off-time delay to enable Legacy IEEE802.3af PoE compatibilty. An internal 0.3-FET provides maximum power delivery. As an additional feature, the TPS2371 interfaces with the enable/soft-start signal of a dc-to-dc converter, eliminating the need to have an accurate UVLO in the dc-to-dc converter.
At low input voltages (1.8 V to 10 V), the TPS2371 draws less than 12 µA, allowing accurate sensing of the external 24.9-kdiscovery resistor. At input voltages between 15 V and 20 V, an external resistor sets the level of current to be drawn during classification mode. TPS2371 is compatible with current as well as voltage measurement schemes for classification. Above 20-V input, the classification current is shut off, reducing internal power dissipation.
The TPS2371 drives an internal low-side FET for control of the return side of the power path. The internal FET is turned on when the input voltage reaches 36 V and above. When the input voltage decreases, the FET remains on until the input voltage drops to below 30 V.
During initial turn-on of the switch (inrush mode), an external resistor is used to program the inrush current, allowing a wide range of capacitor values to be used at the load. According to IEEE 802.3af specification, inrush current of 400 mA is allowed only for 50 ms, limiting the load capacitor to approximately 180 µF. A programmable inrush current limit removes this limitation, allowing a larger capacitor to be used with a lower inrush current limit. |
| Evaluation Boards | 5 | Active | |
| Integrated Circuits (ICs) | 4 | Active | |
| Power Management (PMIC) | 2 | Active | |
TPS23731IEEE 802.3bt type 3 class 1-4 PoE PD with no-opto flyback DC-DC controller | Power Management (PMIC) | 2 | Active | The TPS23731 device combines a Power over Ethernet (PoE) powered device (PD) interface, and a current-mode DC-DC controller optimized for flyback switching regulator designs where the use of primary-side regulation (PSR) is supported. The PoE interface supports the IEEE 802.3bt and IEEE 802.3at standard s for applications needing up to 25.5 W or less at PD input.
Programmable spread spectrum frequency dithering (SSFD) is provided to minimize the size and cost of EMI filter. Advanced Startup with adjustable soft-start helps to use minimal bias capacitor while simplifying converter startup and hiccup design, also ensuring that IEEE 802.3bt /at startup requirements are met.
The soft-stop feature minimizes stress on switching sync FET(s), allowing FET BOM cost reduction.
The PSR feature of the DC-DC controller uses feedback from an auxiliary winding for control of the output voltage, eliminating the need for external shunt regulator and optocoupler. It is optimized for continuous conduction mode (CCM), and can work with secondary side synchronous rectification, resulting in optimum efficiency, regulation accuracy and step load response over multiple outputs.
The DC-DC controller features slope compensation and blanking. Typical switching frequency is 250 kHz.
The automatic MPS enables applications with low power modes or multiple power feeds. It automatically adjusts its pulsed current amplitude and duration according to PSE Type and system conditions, to maintain power while minimizing consumption.
The TPS23731 device combines a Power over Ethernet (PoE) powered device (PD) interface, and a current-mode DC-DC controller optimized for flyback switching regulator designs where the use of primary-side regulation (PSR) is supported. The PoE interface supports the IEEE 802.3bt and IEEE 802.3at standard s for applications needing up to 25.5 W or less at PD input.
Programmable spread spectrum frequency dithering (SSFD) is provided to minimize the size and cost of EMI filter. Advanced Startup with adjustable soft-start helps to use minimal bias capacitor while simplifying converter startup and hiccup design, also ensuring that IEEE 802.3bt /at startup requirements are met.
The soft-stop feature minimizes stress on switching sync FET(s), allowing FET BOM cost reduction.
The PSR feature of the DC-DC controller uses feedback from an auxiliary winding for control of the output voltage, eliminating the need for external shunt regulator and optocoupler. It is optimized for continuous conduction mode (CCM), and can work with secondary side synchronous rectification, resulting in optimum efficiency, regulation accuracy and step load response over multiple outputs.
The DC-DC controller features slope compensation and blanking. Typical switching frequency is 250 kHz.
The automatic MPS enables applications with low power modes or multiple power feeds. It automatically adjusts its pulsed current amplitude and duration according to PSE Type and system conditions, to maintain power while minimizing consumption. |
TPS23734IEEE 802.3bt type 3 class 1-4 PoE PD with high efficiency DC-DC control | Power Management (PMIC) | 2 | Active | The TPS23734 device combines a Power over Ethernet (PoE) powered device (PD) interface, and a current-mode DC-DC controller optimized for flyback and active clamp forward (ACF) switching regulator designs . In the case of flyback configuration, the use of primary-side regulation (PSR) is supported. The PoE interface supports the IEEE 802.3bt and IEEE 802.3at standard s for applications needing up to 25.5 W or less at PD input.
Programmable spread spectrum frequency dithering (SSFD) is provided to minimize the size and cost of EMI filter. Advanced Startup with adjustable soft-start helps to use minimal bias capacitor while simplifying converter startup and hiccup design, also ensuring that IEEE 802.3bt /at startup requirements are met.
The soft-stop feature minimizes stress on switching power FETs , allowing FET BOM cost reduction.
The PSR feature of the DC-DC controller uses feedback from an auxiliary winding for control of the output voltage, eliminating the need for external shunt regulator and optocoupler. It is optimized for continuous conduction mode (CCM), and can work with secondary side synchronous rectification, resulting in optimum efficiency, regulation accuracy and step load response over multiple outputs.
The DC-DC controller features slope compensation and blanking. Typical switching frequency is 250 kHz.
The automatic MPS enables applications with low power modes or multiple power feeds. It automatically adjusts its pulsed current amplitude and duration according to PSE Type and system conditions, to maintain power while minimizing consumption.
The TPS23734 device combines a Power over Ethernet (PoE) powered device (PD) interface, and a current-mode DC-DC controller optimized for flyback and active clamp forward (ACF) switching regulator designs . In the case of flyback configuration, the use of primary-side regulation (PSR) is supported. The PoE interface supports the IEEE 802.3bt and IEEE 802.3at standard s for applications needing up to 25.5 W or less at PD input.
Programmable spread spectrum frequency dithering (SSFD) is provided to minimize the size and cost of EMI filter. Advanced Startup with adjustable soft-start helps to use minimal bias capacitor while simplifying converter startup and hiccup design, also ensuring that IEEE 802.3bt /at startup requirements are met.
The soft-stop feature minimizes stress on switching power FETs , allowing FET BOM cost reduction.
The PSR feature of the DC-DC controller uses feedback from an auxiliary winding for control of the output voltage, eliminating the need for external shunt regulator and optocoupler. It is optimized for continuous conduction mode (CCM), and can work with secondary side synchronous rectification, resulting in optimum efficiency, regulation accuracy and step load response over multiple outputs.
The DC-DC controller features slope compensation and blanking. Typical switching frequency is 250 kHz.
The automatic MPS enables applications with low power modes or multiple power feeds. It automatically adjusts its pulsed current amplitude and duration according to PSE Type and system conditions, to maintain power while minimizing consumption. |
| Development Boards, Kits, Programmers | 11 | Active | |
TPS23750Class 3 PoE PD with flyback DC-DC controller | Power Management (PMIC) | 5 | Active | The TPS23750 integrates the functionality of the TPS2375 with a primary side dc/dc PWM controller. The designer can create a front-end solution for PoE-PD applications with minimum external components. The TPS23770 is identical to the TPS23750 with the exception of the undervoltage lockout turn-on voltage, which is compatible with legacy systems.
The PoE front end has all the necessary IEEE 802.3af functions including detection, classification, undervoltage lockout and inrush control. The PoE input switch is integrated within the TPS23750.
The dc/dc controller section is designed to support flyback, forward, and nonsynchronous low-side switch buck topologies.
The external switching MOSFET and current sense resistor provide flexibility in topology, power level, and current limit. The full-featured dc/dc controller includes programmable soft start, hiccup type fault limiting, 50% maximum duty cycle, programmable constant switching frequency, and a true voltage-output error amplifier. Additional protection features provide for robust designs.
The TPS23750 integrates the functionality of the TPS2375 with a primary side dc/dc PWM controller. The designer can create a front-end solution for PoE-PD applications with minimum external components. The TPS23770 is identical to the TPS23750 with the exception of the undervoltage lockout turn-on voltage, which is compatible with legacy systems.
The PoE front end has all the necessary IEEE 802.3af functions including detection, classification, undervoltage lockout and inrush control. The PoE input switch is integrated within the TPS23750.
The dc/dc controller section is designed to support flyback, forward, and nonsynchronous low-side switch buck topologies.
The external switching MOSFET and current sense resistor provide flexibility in topology, power level, and current limit. The full-featured dc/dc controller includes programmable soft start, hiccup type fault limiting, 50% maximum duty cycle, programmable constant switching frequency, and a true voltage-output error amplifier. Additional protection features provide for robust designs. |
TPS23751IEEE 802.3at PoE interface with flyback DC-DC controller | DC/DC & AC/DC (Off-Line) SMPS Evaluation Boards | 3 | Active | The TPS23751 is a 16-pin integrated circuit that combines a Power-over-Ethernet (PoE) powered device (PD) interface and a current-mode DC-DC controller optimized specifically for applications requiring high efficiency over a wide load range.
The PoE interface implements type-2 hardware classification per IEEE 802.3at. It also includes an auxiliary power detect (APD) input and a disable function (DEN). A 0.5-Ω, 100-V pass MOSFET minimizes heat dissipation and maximizes power utilization.
The DC-DC controller features internal soft-start, a bootstrap startup current source, current-mode control with slope compensation, blanking, and current limiting. Efficiency is enhanced at light loads by disabling synchronous rectification and entering variable frequency operation (VFO).
The TPS23752 is a 20-pin extended version of the TPS23751 with the addition of a Sleep Mode feature. Sleep Mode disables the converter to minimize power consumption while still generating the Maintain Power Signature (MPS) required by IEEE802.3at.
The TPS23751 is a 16-pin integrated circuit that combines a Power-over-Ethernet (PoE) powered device (PD) interface and a current-mode DC-DC controller optimized specifically for applications requiring high efficiency over a wide load range.
The PoE interface implements type-2 hardware classification per IEEE 802.3at. It also includes an auxiliary power detect (APD) input and a disable function (DEN). A 0.5-Ω, 100-V pass MOSFET minimizes heat dissipation and maximizes power utilization.
The DC-DC controller features internal soft-start, a bootstrap startup current source, current-mode control with slope compensation, blanking, and current limiting. Efficiency is enhanced at light loads by disabling synchronous rectification and entering variable frequency operation (VFO).
The TPS23752 is a 20-pin extended version of the TPS23751 with the addition of a Sleep Mode feature. Sleep Mode disables the converter to minimize power consumption while still generating the Maintain Power Signature (MPS) required by IEEE802.3at. |
