一种新颖的BUCK型DC-DC芯片的抗振铃电路

典型的集成Buck型DC-DC变换器,其电感只有一端接入芯片,无法在芯片内部采用Boost型DC-DC在电感两端直接并联电阻的方法进行振铃的快速衰减.文中设计了一种新颖的适用于Buck型DC-DC的抗振铃电路,在芯片内部采用一个线性时变电阻网络将电感的一端与芯片的电源(或地)之间进行连接.进行振铃衰减时,起初电阻较小,振铃衰减很快,但直流电流较大;随着振铃的减弱,逐渐增大电阻以减小直流电流,当振铃结束且直流电流很小时完全断开电阻.这样既达到抗振铃的目的,又不会引起持续的直流放电.采用此电路的一款DC-DC已在韩国Hynix公司的0.5 μ m CMOS工艺线投片,测试结果证明抗振铃效果良好.

A Novel Anti-Ringing Circuit for Buck DC-DC Chip

For typical topology of buck converter,only one terminal of the inductor is connected to the chip.So it is impossible to parallel a resistor with the inductor to damp the ring as it is used in boost converter.A novel anti-ringing circuit is presented to solve this problem.A time varying resistor network is connected between one terminal of the inductor and the power supply or the ground.In the beginning of the ring,a small resistor is used to damp the ring rapidly.But the DC current is large.With the weakening of the ring,the resistance is increased to reduce the DC current gradually.And when the ring disappears and the DC current is small enough,the network is opened.By this way,anti-ringing is achieved and no DC current exists after the ring damping is ended.A DC-DC converter with this anti-ringing circuit has been implemented in Hynix 0.5 μ m CMOS process,the result indicates that it works well and effectively.