TPS54202DDCR Alternatives, Characteristics, Layout and TPS54202DDCR vs TPS54202DDCT
02 April 2024
Ⅱ. Functional modes of TPS54202DDCR
Ⅲ. Characteristics of TPS54202DDCR
Ⅳ. How to reduce the noise of TPS54202DDCR?
Ⅴ. Comparison between TPS54202DDCR and TPS54202DDCT
Ⅶ. How to improve the power efficiency of computers and servers with TPS54202DDCR?
The TPS54202DDCR is a 2A synchronous buck converter with an input voltage range from 4.5V to 28V. The device integrates two switching FETs with internal loop compensation and a 5-ms internal soft-start feature, reducing the number of components required. By integrating MOSFETs and using an SOT-23 package, the TPS54202DDCR achieves high power density while occupying a small footprint on the PCB. Its advanced Eco mode maximizes light load efficiency and reduces power loss. To reduce EMI, the converter also introduces spread spectrum operation. Cycle-by-cycle current limiting in the high-side MOSFET protects the converter during overload conditions, while freewheeling current limiting in the low-side MOSFET prevents runaway current, further enhancing safety. If the overcurrent condition lasts longer than the set threshold, the hiccup mode protection mechanism is triggered.
Alternative models:
1. Eco-mode™ operation
The TPS54202DDCR is engineered to function in high-efficiency pulse-skipping mode during light load conditions, which begins when the switch current drops to 0 A. In pulse skipping, the low-side FET deactivates once the switch current reaches 0 A. This results in the switching node waveform, observable at the SW pin, adopting traits akin to discontinuous conduction mode (DCM), causing a reduction in the apparent switching frequency. With decreasing output current, the interval between switching pulses becomes more pronounced.
2. Normal operation
When the input voltage is above the UVLO threshold, the TPS54202DDCR can operate in their normal switching modes. Normal continuous conduction mode (CCM) occurs when inductor peak current is above 0 A. In CCM, the device operates at a fixed frequency.
• Thermal shutdown
• Peak current mode control
• Internal 5-mS soft start
• Internal loop compensation
• Advanced Eco-mode™ pulse skip
• Fixed 500-kHz switching frequency
• 4.5-V to 28-V wide input voltage range
• Frequency spread spectrum to reduce EMI
• Low 2-µA shutdown, 45-µA quiescent current
• Overvoltage protection
• Overcurrent protection for both MOSFETs with hiccup mode protection
• Integrated 148-mΩ and 78-mΩ MOSFETs for 2-A, continuous output current
We can take the following measures to reduce the noise of TPS54202DDCR.
1. Load management
We need to consider the connection distance between the load and the power supply, try to keep a short distance connection, which can reduce the loss of current in the transmission process and improve the efficiency of the power supply. Secondly, we should choose a good conductivity, stable and reliable connection line to ensure stable current transmission.
2. Component selection
We need to pick low noise inductors. These inductors have excellent electromagnetic shielding performance to reduce the impact of electromagnetic interference on the circuit. At the same time, their inductance value should be accurate and stable to ensure the stability and reliability of the circuit. The selection of capacitors, as indispensable components in the circuit, is equally important. Low-noise capacitors should have a low equivalent series resistance (ESR), which significantly reduces circuit losses at high frequencies and lowers the noise level at the input. In addition, the capacitor capacity and voltage rating should be precisely matched to the specific design requirements to ensure stable circuit operation.
3. Layout optimization
During the design process, we should not only ensure that the input, output and ground pins are correctly connected to prevent the introduction of unnecessary noise due to improper connection, but also ensure that the ground loop is as short as possible and separated from the signal loop to reduce the generation of common mode noise. In addition, we should also effectively separate the sensitive signal lines from the high current loop.
4. Circuit design
When crafting filters for electronic circuits, it is imperative to handle both input and output noise. Addressing high-frequency noise at the input can be achieved by integrating a low pass filter, which efficiently eliminates the unwanted noise. To tackle high-frequency noise on the input side, incorporating a low pass filter effectively filters out unwanted signals. Meanwhile, on the output end, an LC filter, comprising an inductor and capacitor, proves effective in mitigating noise. Additionally, we need to select low equivalent series resistance (ESR) output capacitors to help reduce noise while ensuring stability requires adequate capacitor size for stable output.
By comparing the two chips TPS54202DDCR and TPS54202DDCT, we can clearly see that in addition to output voltage and packaging form, they show a high degree of consistency in other technical characteristics.
1. Layout guidelines
(1) Do not allow switching current to flow under the device.
(2) Make a Kelvin connection to the GND pin for the feedback path.
(3) The trace of the VFB node should be as small as possible to avoid noise coupling.
(4) Provide sufficient vias for the input capacitor and output capacitor.
(5) Keep the SW trace as physically short and wide as practical to minimize radiated emissions.
(6) A separate VOUT path should be connected to the upper feedback resistor.
(7) The GND trace between the output capacitor and the GND pin should be as wide as possible to minimize its trace impedance.
(8) Voltage feedback loop should be placed away from the high-voltage switching trace, and preferably has ground shield.
(9) The input capacitor and output capacitor should be placed as close to the device as possible to minimize trace impedance.
(10) VIN and GND traces should be as wide as possible to reduce trace impedance. The wide areas are also of advantage from the view point of heat dissipation.
2. Layout example
Some methods are listed below:
1. Utilize the enable function: With the enable function of TPS54202DDCR, we can control the power on and off according to the system demand. When the device is not in use, we can turn off the power supply to reduce energy consumption.
2. Choose the right output voltage: We set the output voltage of TPS54202DDCR according to the voltage requirements of different components in computers and servers. This can avoid over powering and reduce energy consumption.
3. Optimize layout and wiring: During PCB design, we should optimize the layout and wiring of the power converter to reduce noise and electromagnetic interference. This can improve power conversion efficiency and reduce system energy consumption.
4. Use appropriate external components: In order to maximize power efficiency, we need to select appropriate external components such as inductors, capacitors and resistors. These components should be characterized by high stability, low loss and small size.
5. Adjust switching frequency: We should adjust the switching frequency of TPS54202DDCR according to the system requirements to optimize the power conversion efficiency. Higher switching frequency may lead to higher power consumption, so we need to find a balance between efficiency and cost.
6. Adopt multiple output design: If there are multiple voltage requirements in computers and servers, we can consider adopting a multiple output design to meet the power supply requirements of different components. This can avoid unnecessary voltage conversion and reduce energy consumption.
Frequently Asked Questions
1. What is a buck converter used for?
A buck converter is used to step down voltage of the given input in order to achieve required output. Buck converters are mostly used for USB on the go, point of load converters for PCs and laptops, Battery Chargers, Quad Copters, Solar Chargers, and power audio amplifiers.
2. Does TPS54202DDCR have built-in protection features?
Yes, TPS54202DDCR includes various protection features such as thermal shutdown, overcurrent protection, and undervoltage lockout to enhance system reliability and safety.
3. What is the purpose of TPS54202DDCR?
TPS54202DDCR is designed to efficiently convert a higher input voltage to a lower output voltage, making it suitable for a wide range of applications such as power supplies, battery chargers, and LED drivers.
