Resonant Regulating Rectifiers (3R) Operating for 6.78 MHz Resonant Wireless Power Transfer (RWPT)

An Overview of Regulation Topologies in Resonant Wireless Power Transfer Systems for Consumer Electronics or Bio-Implants

“…This scheme adopts a rectifier cascaded by a regulating stage as shown in Figure 4. Both the LDO [12][13][14][15] and the DC-DC converter [16][17][18][19][20] can be implemented as the cascaded stage. These schemes are discussed as follows.…”

“…To eliminate the bulky inductor in [16], a resonant regulating rectifier (3R) was proposed in [17]. The working principle of this 3R scheme is illustrated in Figure 7a, where a switch S 1 is inserted between the rectifier and the load.…”

“…This results in a higher coil power loss represented by I RX-RMS 2 ×R 2 , where R 2 represents the L RX resistance. To reduce the RMS resonant current, a three-switch 3R scheme working in CCM was also presented in [17]. The working principle of this scheme is shown in Figure 8.…”

“…Therefore, the regulation schemes investigated in the previous works can also be categorized into two types: RX and TX regulation. As illustrated in Figure 3, RX regulation includes post-stage regulation (achieved by a cascading low dropout regulator (LDO [12][13][14][15] or a DC-DC converter [16][17][18][19][20]) and one-stage regulation, including active diode conduction time control [21][22][23], reconfigurable regulating rectification [24][25][26][27], and switching-based current-mode regulation [28][29][30][31]. On the other hand, TX regulation can be achieved by PA supply voltage control [32,33], resonant frequency control [34], PA power switch duty cycle control [35][36][37][38][39][40], and vector power summing control [41,42].…”

A unified DLL-controlled active rectifier in 6.78 MHz resonant-coupling wireless power receivers for space-limited portable and wearable applications

“…Compared to the inductive-coupling WPT, the resonant-coupling WPT is a more attractive method, since it maintains high efficiency even the distance between the transmitter and the receiver is far more several meters [1]. However, since the specified portable and wearable devices may have space and cost limitations, the devices exploit a small rechargeable solid-state thin battery or coin cell battery [2,3], which has a lower charging current than the mobile phone battery.…”