For the next Generation of Household Appliances Power Supply, How to "gather the Armpit into a Fur"?

It is very popular to add new functions to household appliances. For example, when the washing cycle is completed, the washing opportunity sends a message; Or send pictures on the screen or by email to show the inside of the refrigerator. These additional functions require new subsystems, such as wireless communication, sensors, human machine interface (HMI) and lighting, all of which require power supply.

Figure 1: Design of high efficiency 5V, 1A switching power supply with t0-220 shape factor

At the same time, electrical appliances need to consume as little power as possible in order to limit their impact on the environment, reduce consumers' power costs, and successfully pass increasingly stringent energy ratings.

In addition, cost, size and reliability are always key requirements.

Low dropout voltage regulator (LDO) is traditionally used in household appliances to generate 5V or 3.3V voltage from 12V voltage rail. But the efficiency of LDO is really poor. Figure 2 compares the power consumption of 12V input and 5V output in LDO and high efficiency DC / DC switching mode power supply (SMPS) reference design in TO-220 shape factor and output current.

Figure 2: relationship between power consumption and output current of LDO and DC / DC switching mode power supply

As expected, the efficiency of LDO is very low, which is why its maximum output current is limited; It also needs a large volume radiator to dissipate the loss. No heat sink is required in the DC / DC converter, and all four reference designs include the tps54202 step-down converter.

You can use DC / DC converters to convert 12V to 5V or 3.3V to achieve higher efficiency and higher current drive capability to power multiple new subsystems. In addition, this will reduce the input current consumed and help the appliance pass a strict energy rating.

Ti has four reference designs to solve these problems:

Double layer TO-220 refers to 5V 1a, low EMI, 94% efficiency DC / DC SMPS in the design.

Double layer TO-220 refers to the 3.3V 1a, low EMI, 92% efficiency DC / DC SMPS in the design.

Single layer TO-247 shape refers to 5V 1a, low EMI, 94% efficiency DC / DC SMPS in the design.

Single layer TO-247 shape refers to 3.3V 1a, low EMI, 92% efficiency DC / DC SMPS in the design.

All four SMPS reference designs are compatible with the TO-220 package pins traditionally used for LDOS in devices, so in the evaluation / redesign phase, rapid evaluation can be carried out by exchanging LDOS with DC / DC reference designs.

Other information

Relevant application notes:

Understand the step-down power level in switching mode power supply.

Linear and switching regulators for industrial applications using 24 V bus

Review the following guidelines:

Air conditioning solution guide

Refrigerator and refrigeration Solutions Guide

Washer and dryer solution guide