A simple circuit to remove X-cap bleeder resistor for reducing standby power consumption

A simple circuit is introduced in this paper for eliminating power dissipation of bleeder resistor when the power converter is plugged to the power outlet. The depletion-type NMOS device can be naturally turned-on to establish discharge path of X capacitor without driving voltage for safety consideration. And the depletion-type NMOS device is virtually turned off to disconnect bleeder resistor for improving the efficiency of power converter while AC power is on. As a result, the waste power can be removed in normal operation, light load, especially in standby load conditions for comply the newest energy star specification, EuP lot 6 and 5 star standards of mobile charger standby power regulations. Experimental results demonstrate that the proposed scheme can implement ultra low standby power of converter with a simple and low cost solution. References: [1] J. Hu, H. Chen, Q. Wang, X. Li, X. Fan, X. Li, Y. Lei, and Z. Song: IEICE Electron. Express 12 (2015) 20150901. [2] W. Nie, J. Wu, and Z. Yu: IEICE Electron. Express 10 (2013) 20130756. [3] C. L. Yeh, T. W. Hou, and C. M. Chao: IEICE Electron. Express 6 (2009) 1757. [4] Fairchild semiconductor, Design guidelines for new-generation FPSTM www.fairchildsemi.com/application-notes/AN/AN-9752.pdf [5] Safety requirements for electrical equipment for measurement, control, and laboratory use. IEC 61010-1 3rd Edition, Jun. 2010. [6] ENERGY STAR eligibility criteria (version 2.0) draft 1. Program requirements for single voltage external ac-dc power supplies. [7] EuP preparatory study lot 6, standby and off-mode losses. Eco-design requirements for energy using products, European Union. [8] https://en.wikipedia.org/wiki/No_load_power. [9] K. K. Kim, and Y. B. Kim: IEICE Electron. Express 5 (2008) 556. [10] J. W. Chun, and C. Y. R. Chen: IEICE Electron. Express 13 (2016) 20151052. [11] https://prodcuts.niko-sem.com