key word:AC, USB, charging, adapterAuthor: adnaan lokhandwala, product manager, Texas Instruments (TI)
Universal serial bus (USB) charging has become a common power supply method for small electronic products. Many new consumer electronic devices (e.g. smart phones, tablets, e-readers, etc.) have AC power adapters / battery chargers with a power range of 5 to 25W and have a USB standard a interface. 5V adapter output voltage has become the first choice for charging and communication of compatible PC / desktop port. At present, the mainstream connection method is to use a standard (mini or micro-b) USB cable, while in most cases, non-standard connectors are used. As people pay more attention to battery charging, the old "block brick adapter" is becoming a cool, light, fashionable, safe and green charger. In addition to meeting standard conditioning requirements, OEMs continue to break the performance limitations of adapter efficiency and no-load power consumption (standby power consumption). For example, major mobile phone charger manufacturers have consistently implemented a five-star (no-load power consumption less than 30 MW) charger power rating system. This makes it easier for consumers to compare and choose those energy-efficient chargers.
Recently, there has been a heated discussion on how to standardize mobile phone input and how to produce a universal charger that can charge all mobile phones. In 2006, China issued a new regulation aimed at standardizing wall chargers and their connecting wires. Coincidentally, the GSM Association (GSMA) is also leading the development of the "universal charging solution" adapter plan, which aims to power mobile phones with micro USB interface. The ordinary charger is required to provide 5V 5% voltage, the minimum current is 850 Ma, and the no-load power consumption is less than 150 MW. In addition, it must comply with USB Design Forum (usb-if) battery charging specification 1.1 (bc1.1)* In addition to being convenient for consumers, standardized chargers can also reduce a large number of redundant chargers. In addition, the AC adapter with multiple USB jacks allows consumers to easily charge a variety of electronic devices without using many special chargers. Some high output current chargers also allow fast battery charging. This is an important advantage over the standard USB 2.0 port that limits the current of 500mA. People's demand for these improved performance is increasing, and the adapter design is becoming more and more miniaturized, which makes the thermal management in this "black box" a huge problem in front of the majority of power supply designers.
Power Architecture
Considering the power consumption, the reverse topology shown in Figure 1 has become our first choice because of its simplicity and low cost. The conduction loss of the Schottky diode rectifier on the secondary side (Fig. 1a) has become a limiting factor for realizing high-efficiency and compact adaptation design. For example, in a typical 5-V / 3-A adapter, the power loss of diode rectifier itself can reach 30% to 40% of the total system loss under full load (ignoring the comprehensive impact of secondary loss on high primary side loss). Installing a synchronous rectifier (SR) for the output (Fig. 1b) can improve the overall efficiency of the converter, and the system thermal management is easier due to the less heat generated (which is crucial in the adapter design).
Figure 1 Simplified reverse topology2012-8-2 15:40:53 uploadDownload attachment (41.79 KB)
Uploaded at 15:40:00 on August 2, 2012Uploaded at 15:40:00 on August 2, 2012Uploaded at 15:38:37 on August 2, 2012
Uploaded at 15:40:00 on August 2, 2012
Bao’an District Shenzhen City, China
+86 189 3806 5764
{"site":{"site_id":3908,"site_type":11,"site_domain":"laptoprepair.com","domain_mode":1,"original_domain":"laptoprepair.com","language_code":"en","is_init_domain":0,"is_shop":true,"is_ssl":1,"lang_prefix":"/","animate_name":"none","compress__ratio":"100,100,100"},"page":{"page_id":25858,"page_type":"ai_article_detail","page_code":423,"page_url":"/usb-charging-solution-efficient-ac-adapter1.html","page_source":"","allowAnimat":0,"content_id":216,"content_type":5,"detail_thumb":"https://img.yfisher.com/1650968389690.jpg","detail_title":"USB Charging Solution: Efficient AC Adapter","moq":1},"translateList":{"A new item has been added to your Shopping Cart":"A new item has been added to your Shopping Cart","Account is not exists":"Account is not exists","Add a review on the product":"Add a review on the product","Add to":"Add to","Add to Cart":"add to cart","all":"all","All Orders":"All Orders","Already commented":"Already commented","Are you sure you want to delete it?":"Are you sure you want to delete it?","Are you sure to delete the selected items?":"Are you sure to delete the selected items?","Awaiting Payment":"Awaiting Payment","Awaiting Shipment":"Awaiting Shipment","account security":"account security","address book":"address book","Buy":"Buy","Buy Now":"Buy Now","Cancel":"cancel","Clear":"Clear","Clear Search":"Clear Search","Confirm":"Confirm","Choose a country":"Choose a country","Choose Coupon":"Choose Coupon","commodity payment":"commodity payment","Completed":"Completed","Condition not met":"Condition not met","Confirm password is inconsistent with new password":"confirm password is inconsistent with new password","Congratulations":"Congratulations","Congratulations! You are got a coupon.":"Congratulations! You are got a coupon.","Congratulations! You are got all coupons.":"Congratulations! You are got all coupons.","Continue Shopping":"Continue Shopping","Copy the code and use it directly in the shopping cart.":"Copy the code and use it directly in the shopping cart.","Coupon List":"Coupon list","Country":"Country","Design customization":"Design customization","Do not use any discount":"Do not use any discount","Earliest":"Earliest","email":"email","email format does not match":"email format does not match","Estimated Delivery Time":"Estimated Delivery Time","expired":"expired","Find Parts":"Find Parts","Free":"Free","Free Quote & Information Request":"Free Quote & Information Request","Free Shipping":"Free Shipping","for order over":"for order over","Get":"Get","Get coupons":"Get coupons","Get discount":"Get discount","Get it":"Get it","Get it after logging in and use it in the shopping cart.":"Get it after logging in and use it in the shopping cart.","Go to Page":"Go to Page","Highest Price":"Highest Price","Hot Sale":"Hot Sale","home":"home","Incorrect form format":"Incorrect form format","inquiry":"inquiry","Loading":"Loading","Lowest Price":"Lowest Price","Match Product":"Match Product","Merchant Free Shipping":"Merchant Free Shipping","Most Popular":"Most Popular","my account":"my account","my coupons":"my coupons","my inquiry":"my inquiry","my orders":"my orders","my reviews":"my reviews","my wishlist":"my wishlist","name":"name","Newest":"Newest","No Quotation":"No Quotation","No time limit":"No time limit","Not deleted":"Not deleted","not valid yet":"not valid yet","Off":"Off","Offers and Discounts":"Offers and Discounts","ok":"ok","optional":"optional","Order over":"Order over","order notes":"order notes","Password contains at least numbers and letters length should be 6-20":"password contains at least numbers and letters length should be 6-20","Password is invalid":"Password is invalid","Password length should be 6-20":"Password length should be 6-20","Paypal":"Paypal","paypal payment":"paypal payment","personal info":"personal info","Please click ’click to continue’ to retry.":"Please click \"click to continue\" to retry.","Please enter a valid email address":"Please enter a valid email address","Please enter the verification code":"Please enter the verification code","Please login in first":"Please login in first","Please select attribute":"Please select attribute","Please select country/region":"Please select country/region","Please select superior":"Please select superior","Please select the number of ratings.":"Please select the number of ratings.","read more":"read more","Region":"Region","Register Success":"Register Success","Sale ends in":"Sale ends in","Save in wishlist":"Save in wishlist","Search":"Search","Shipping":"Shipping","Shipping Address":"shipping address","shipment successful":"shipment successful","Size guide":"Size guide","Small Text":"Small Text","Small Title":"Small Title","Sort By":"Sort By","State/Province/Territory":"State/Province/Territory","Successfully delete":"Successfully delete","Successfully save":"Successfully save","The coupon code has been copied and used in the shopping cart.":"The coupon code has been copied and used in the shopping cart.","The subscription is successful, thank you for your participation":"The subscription is successful, thank you for your participation","The user center is out of service. Please contact customer service":"The user center is out of service. Please contact customer service","This is Text":"This is Text","This is title":"This is title","This transaction has failed.":"This transaction has failed.","Time to shop":"Time to shop","To be commented":"To be commented","Total":"Total","the content can not be blank":"the content can not be blank","Update password success":"Update password success","Upload Image":"Upload Image","Upload up to 6 pictures":"Upload up to 6 pictures","uploading":"uploading","used":"used","user center":"user center","Validity period":"Validity period","valid now":"valid now","View Cart & Checkout":"View Cart & Checkout","Welcome to the website":"Welcome to the website","Western Union":"Western Union","Write a Review":"Write a Review","You are got a coupon.":"You are got a coupon.","You haven’t chosen an address yet":"You haven't chosen an address yet","You haven’t selected a product yet":"You haven't selected a product yet","Your rating":"Your rating","Your review":"Your review","Your shipping address error":"Your shipping address error"}}