半桥驱动器 : 采用变压器还是全硅驱动? Half-Bridge Drivers A Transformer or an All-Silicon Drive?

www.onsemi.cn 半桥驱动器 : 采用变压器还是全硅驱动? Half-Bridge Drivers A Transformer or an All-Silicon Drive?

议程 Agenda 使用半桥配置的拓扑结构 Topologies using a half-bridge configuration 软开关与硬开关的区别 The difference between soft and hard-switching 门驱动变压器 The gate-drive transformer 全硅方案 The all-silicon-solution 比较 Comparison 总结 Summary 2

硬开关 Hard Switching 反激 Flyback 高能效拓扑结构趋势 Topology Trend for High Efficiency 软开关 Soft Switching LLC 半桥谐振 LLC-HB resonant 正激 Forward 双开关反激 2-sw flyback 双开关正激 2-sw forward 全桥 Full bridge 有源钳位正激 Active clamp forward 有源钳位反激 Active clamp flyback 不对称半桥 (AHB) Asymmetrical half-bridge 相移全桥 Full bridge with phase shift 有源钳位正激 Active clamp Forward 不对称半桥 AHB 双电感加单电容半桥 LLC-HB 有源钳位反激 Active clamp Flyback 相移全桥 FB Phase-shift 4

高端开关 The High-Side Switch 要提供高能效, 首选带零电压开关 (ZVS) 特性的拓扑结构 To achieve high efficiency, the topologies with ZVS (Zero-Voltage Switching) behavior are preferred. 所有软开关拓扑结构应用带浮点参考引脚的电源开关, 如 MOSFET 的源极引脚 All the soft switching topologies implement the power switch with floating reference pin, e.g. the source pin of MOSFET. 为什么软开关应用中使用 MOSFET? Why are MOSFETs used in soft switching applications? 高频工作 High frequency operation 体二极管 (ZVS 电流环路 ) Body diode (current loop for ZVS) 如何驱动高端 MOSFET? How to drive the high side MOSFET? 5

硬开关导通过程 Turn-on Procedure for Hard-switching 米勒效应平台 The Miller plateau V GS V DRV D I D V TH V GS,Miller C GD R HI R GATE G R G,I C DS I G I G C GS S V DS 米勒效应平台由 C GD 导致 The miller plateau is caused by C GD I D 第二 (S2) 第三 (S3) 阶段占 MOSFET 及 S 1 S 2 S 3 S 4 驱动器开关损耗的主要部分 Stages 2 and 3 dominate the switching losses of MOSFET and driver. V GS 接近 V GS, Miller 时驱动器 (DRV) 的源极能力很重要 DRV s source capability as V GS is around V GS,Miller is important. 7

硬开关的关闭过程 Turn-off Procedure for Hard-switching 米勒效应平台 The Miller plateau V GS,Miller V DRV D I D V GS V TH C GD R LO R GATE G R G,I C DS I G I G C GS S V DS 米勒效应平台由 C GD 导致 The miller plateau is caused by C GD I D 第二 (S2) 第三 (S3) 阶段占 MOSFET 及 S 1 S 2 S 3 S 4 驱动器开关损耗的主要部分 Stages 2 and 3 dominate the switching losses of MOSFET and driver. V GS 接近 V GS, Miller 时驱动器 (DRV) 的汲极能力很重要 DRV s sink capability as VGS is around VGS,Miller is important. 8

反激仿真电路 Simulation Circuit of Flyback Iout Rp 300m RATIO_POW = -0.0667 RATIO_AUX = -0.0667 2 7 X1 MBRS340t3 Out Vout 17 Vin 250 Out R11 3.9k 22 Vclipp C6 47pF Δ Isnub Iclipp Cclamp 1.4nF Rclamp 88k 10 D3 MUR160 Lp 1.75mH Ip 1 5 Ll 0.1uH 18 D1 1N4148 Aux R9 300m 21 C5 10uF Resr 100m 16 C2 440uF Rload 2.5 Rupper 4.851k 11 R17 20k Ipri Verr V1 C7 470pF 6 Vdrain C4 3.97nF 9 Vramp 12 X2 PWMCM CMP FB OUT OSC GND 23 SENS Vdrv Rg 15 D2 1N4148 Vgs 3 X3 IRF840 Aux R5 470 I DS Rlower 0.97k C1 470pF 14 R13 1k 13 Rsense 1 Vsense 仿真反激电路上的 V GS V DS 及 I DS Simulate the V GS, V DS, and I DS on Flyback. 9

反激电路导通仿真 Turn-on Simulation of Flyback plot1 vgs in volts 16.0 12.0 8.00 4.00 0 VGS 1 2 V / div 50 ns / div 700 200 V / div plot3 vdrain in volts 500 300 100-100 VDS 2 50 ns / div 1.20 plot2 ipri in amperes 800m 400m 0-400m IDS 3 200 ma / div 50 ns / div 1.01995m 1.02005m 1.02015m 1.02025m 1.02035m time in seconds V GS 上升时有米勒效应 V GS rises with Miller effect. 10

反激电路关闭仿真 Turn-off Simulation of Flyback plot1 vgs in volts 16.0 12.0 8.00 4.00 VGS 2 V / div 100 ns / div 0 1 700 200 V / div plot3 vdrain in volts 500 300 100-100 VDS 2 100 ns / div 1.20 plot2 ipri in amperes 800m 400m 0 IDS 3 200 ma / div 100 ns / div -400m 1.0244m 1.0246m 1.0248m 1.0250m 1.0252m time in seconds 关闭时存在米勒效应 Turn off with Miller effect. 11

软开关导通过程 Turn-on Procedure for Soft-switching V GS 由于零电压开关 (ZVS), 导通时没有米勒效应 Because of ZVS, there is no Miller effect as turning on. V TH I G 开关损耗的主要决定因素 The switching losses are dominated by 死区时间 ( 以缩短 S 1 ), 及 The dead time (to reduce S 1 ), and V DS 给 C GS 充电以缩短 S 2 的电源供应能力 Source capability to charge C GS to reduce S 2 -V f I D 驱动能力要求较低 Less driver capability requirement. S 1 S 2 S 3 I D 取决于拓扑结构 I D depends on topology 12

软开关关闭过程 Turn-off Procedure for Soft-switching 米勒效应平台 The Miller plateau V GS I G V DS V GS,Miller V TH 类似于硬开关 : 关闭时存在米勒效应 Similar as hard-switching: The Miller plateau exists as turning off. 区别在于 I DS 在关闭期间还降低, 因为在 V DS 改变时 I DS 将经过相反方向的 MOSFET The difference is that I DS also reduces at this duration since I DS will go through the opposite MOSFET as V DS changes. 为了避免 2 个 MOSFET 之间的相位交迭, 将 S 1 ~ S 4 的持续时间减至最短 To avoid overlap between 2 MOSFETs, minimize the duration of S 1 ~ S 4. I DS 需要强大的 DRV 汲极能力 Strong DRV s sink capability is needed. S 1 S 2 S 3 S 4 13

LLC 半桥仿真电路 Simulation Circuit of LLC-HB V3 {Vbulk} D2 1N4148 IM1 26 * WV3 V10 23 R11 15 22 5 M1 IRF840 Δ YM1 I MU B1 Voltage Mupper Δ R10 5m X12 MBR2045? V(G2) < 2.5? 0 : 15 24 D3 1N4148 R14 15 B2 Voltage 19 Vbridge Mlower 10 12 Ls {Ls} 11 V4 IML M2 IRF840 ILmag I ML ICs Vcs 2 Lmag {Lmag} Cs {Cs} Cs Δ VLmag X3 XFMR-TAP RATIO = 1/N 1 X13 MBR2045 4 I CS 仿真 LLC-HB 上的 V GS_MU V DS_MU 及 I MU Simulate the V GS_MU, V DS_MU, and I MU on LLC-HB 为简化电流读取,I MU 和 I ML 的方向参考 I CS To ease the reading of current, the direction of I MU and I ML is referred to I CS. 14

plot1 mlower, mupper in volts 14.0 10.0 6.00 2.00-2.00 LLC 半桥导通仿真 Turn-on Simulation of LLC-HB VGS_ML VGS_MU 1 2 2 V / div 200 ns / div 400 200 V / div plot2 ym1 in volts 300 200 100 VDS_MU 200 ns / div 0 3 plot3 im1, iml in amperes 2.00 1.00 0-1.00-2.00 I_ML I_MU 不会重叠 ; 这是流过 C DS 的电流 5 4 500 ma / div 200 ns / div Not overlap; it is the current through C DS 10.1922m 10.1926m 10.1930m 10.1934m 10.1938m time in seconds V GS_ML 关闭,I CS 减小 V DS, 用于 ZVS V GS_ML off, I CS reduces V DS_MU for ZVS. V DS_MU 在 V GS_MU 之前到达 0 V, 因此 V GS_MU 平滑上升 V DS_MU is 0 V BEFORE V GS_MU, so V GS_MU rises smoothly. 15

Plot1 mlower, mupper in volts 14.0 10.0 6.00 2.00-2.00 LLC 半桥半闭仿真 Turn-off Simulation of LLC-HB VGS_MU VGS_ML 1 2 2 V / div 100 ns / div 400 3 200 V / div Plot2 ym1 in volts 300 200 100 VDS_MU 100 ns / div 0 2.00 Plot3 iml, im1 in amperes 1.00 0-1.00-2.00 I_MU VGS_ML 45 500 ma / div 100 ns / div 10.1976m 10.1978m 10.1980m 10.1982m 10.1984m time in seconds 要示强大的关闭能力 Strong turn off capability is required. 16

驱动器硬开关与软开关比较 Driver Comparison Between Hard-Switching and Soft-Switching 源极能力要求 Source capability requirement 汲极能力要求 Sink capability requirement 死区时间精度要求 Dead time accuracy requirement 硬开关 Hard-switching 中等 Medium 高 High 精确 Accurate 软开关 Soft-switching 低 Low 高 High 精确 Accurate 17

高端驱动器方案 The Solutions for High-Side Driver 基于变压器的方案 Transformer-based solution 单 DRV 输入 Single DRV input 双 DRV 输入 Dual DRV inputs 硅集成电路驱动器 : 双输出 Silicon integrated circuit driver: dual outputs 单 DRV 输入 Single DRV input 双 DRV 输入 Dual DRV inputs 18

驱动变压器设计考虑因素 Consideration as Designing Driver Transformer 对地参考点的浮动驱动 - 如果存在 400 V 预稳压功率因数校正 (PFC) 电路, 则保持 500 V 隔离 Ground-referenced floating drive keep 500-V isolation if a 400-V pre-regulated PFC exists. 将漏电感减至最小 - 输出与输入绕组间的延迟可能会损坏功率管 MOSFET Minimize the leakage inductance - the delay between output and input windings may kill the power MOSFETs. 遵守法拉第定律 - 保持 V*T 恒定, 否则会饱和 Follow Faraday s law keep V*T constant, otherwise, saturate. 保持足够裕量, 防止饱和 - 尤其在交流 (AC) 高压输入和瞬态负载的情况下 Keep enough margin from saturation the worst case happens with transient load at high line. 使用高磁导率铁芯 - 将 I M 降至最低 High permeability ferrite minimize the I M. 保持高汲电流能力, 以加快开关功率管 Keep high sink current capability 20

DRV 死区时间产生器 Dead time generator 单驱动器输入 Single DRV Input V C + - R C C C 驱动器 Driver R GS V DRV -V C -V C V C = DV DRV 1 L Q > R C 1 C L M C M RC = 2 Q CC = 0.5 L C C C 复位驱动器变压器, R C 抑制 L-C 谐振 C C to reset the driver transformer and R C to damp the L-C resonance. M C 需要加交流耦合电容 (C c ) 来复位驱动器变压器磁通 An ac coupling capacitor (C C ) is needed to reset the driver transformer flux. V GS 幅度取决于占空比 The amplitude of V GS is dependent on duty. 稳态时 -V C 关闭, 而在启动时汲电流能力受限 With (-V C ) to turn off at steady state, but the sink capability is limited at start-up. 需要快速的时间常数 (L M //R GS * C C ), 防止由快速瞬态导致的磁通走漏 Need a fast time constant (L M //R GS * C C ) to avoid flux walking due to the fast transient. 留意跳周期模式或欠压锁定 (UVLO) 时 C C 与驱动变压器之间的振铃, 需要使用二极管来抑制振铃 Watch out the ringing between C C and drive transformer at skip mode or UVLO, a diode is needed to damp the ringing. 21

带直流复位的单 DRV 输入 Single DRV Input with DC Restore V DRV -V f 死区时间产生器 Dead time generator 驱动器 Driver -V f V C = DV DRV V C + - R C C C1 V C -V f - + C C2 R 2 C L C M C DRV R GS 稳态时 V GS 幅度取决于占空比 V GS amplitude is independent on duty ratio at steady state. 汲电流能力有限 Limited sink capability. 22

单 DRV 输入, 带 PNP 关闭 Single DRV Input with PNP Turn-Off 死区时间产生器 Dead time generator 驱动器 Driver DRV PNP 晶体管 + 二极管帮助改善关闭 A pnp transistor + diode help to improve the switching off. 23

别忽略 AND 门 Don t Forget the AND Gate 死区时间产生器 Dead time generator 高端驱动器 High-side Driver C C1 C C2 DRV 如果 AND 门驱动能力有限, 增加图腾柱驱动器 Add the totem-pole drivers if output capability of AND gate is limited. 设计是否已经完成? Is the design finished? 还没有注意跳周期模式或欠压锁定 (UVLO) 时 C C1 C C2 及驱动变压器间的振铃 No, not yet. Pay attention to the ringing among C C1, C C2 and driver transformer when skip or UVLO. A diode and resistor to damp the ringing. 24

双极性对称 DRV 输入 Dual Polarity Symmetrical DRV Inputs 驱动器 Driver V DRV -V DRV V DRV DRV A -V f R off DRV B R off DRV A 与 DRV B 极性相反, 位置对称 DRV A and DRV B are opposite-polarity and symmetrical 无交流耦合电容 no ac coupling capacitor. 适合推挽型电路, 如 LLC-HB, 但不适合不对称电路, 如非对称半桥 (AHB) 或有源钳位 This is suitable for push-pull type circuit, e.g. LLC-HB, but NOT for asymmetrical type, e.g. AHB or active clamp. 注意线路 / 负载瞬态时的驱动器变压器磁通 Pay attention to the flux of driver transformer at line/load transient. 仍然需要强大的关闭能力 The strong turn off capability is still needed. 注意由泄漏电感导致的延迟 Pay attention to the delay caused by the leakage inductance. 将泄漏电感减至最小, 并使用双输出绕组而非单输出绕组 minimize the leakage inductance and use dual output windings instead of single output winding. 由 R off 压降导致额外的损耗 Extra losses caused by voltage drop on R off. 25

驱动变压器 The Driver Transformer 优势 Pros 变压器比裸片更强固! A transformer is more robust than a die! 对杂散噪声及高 dv/dt 脉冲较不敏感 Less sensitivity to spurious noise and high dv/dt pulses 更便宜? Cheap? 劣势 Cons 电路复杂 Complicated circuits 需注意极端线路 / 线路条件及关闭模式 Pay attention on extreme line/line condition & off mode 需注意泄漏电感及隔离 Pay attention on the leakage inductance and isolation 汲电流能力是否够强? Is the sink capability strong enough? 26

硅半桥驱动器原理 Silicon Half Bridge Driver Principle 原理 Principle 单输入或双输入 Single or dual inputs 高端或低端驱动器 High & low side driver 集成半桥驱动器 Integrated HB driver 单输入 Single Input in Vcc Gnd out VBoot DRV_HI GND_HI LLC 转换器 LLC converter Vbulk M1 集成半桥驱动器 Integrated HB driver Vbulk IN Dead Time in Vcc Gnd out Vcc DRV_LO M2 IN_HI in Vcc out VBoot DRV_HI M1 GND Gnd GND_HI Vcc IN_LO in Vcc out DRV_LO M2 Gnd GND C1 双输入 Dual Inputs 28

硅方案有何局限? Silicon Solution, What are its Limits? 高端隔离 - 硅片内电压达 600 V High-side isolation 600 V is reached within the silicon. 高端与低端驱动间的匹配传播延迟防止使用任何不平衡变压器 Matched propagation delay between high and low side drive Prevents any unbalanced transformer usage. 高端驱动器的工作电源 - 需要自举电源 High side driver supply Bootstrap supply is requested. 高抗干扰性 - 高端驱动器的负电压强固性 Noise immunity Negative voltage robustness of the high side driver. 29

硅方案, 高压隔离 Silicon Solution, High Voltage Isolation 电平转换器维持高达 600 V Level shifter sustains up to 600 V IN_HI Pulse Trigger Level Shifter 浮动区域 Floating area S R Q in Vcc Gnd out VBoot DRV_HI GND_HI Vbulk M1 IN_LO in Vcc Gnd out Vcc DRV_LO M2 GND 脉冲触发器 : 在 IN_HI 输入的每个边沿产生脉冲 Pulse trigger: generates pulse on each edge from IN_HI input. 电平转换器 : 将脉冲从 GND 参考转换至 GND_HI 参考 Level shifter: shifts pulses from GND reference to GND_HI reference. 同步整流触发器 : 闩锁源自电平转换器的脉冲信息 SR flip flop: latches pulses information from the level shifter. 30

硅方案, 匹配传播延迟 Silicon Solution, Matched Propagation Delay Vbulk VBoot IN_HI Pulse Trigger Level Shifter S R Q in Vcc Gnd out DRV_HI GND_HI M1 IN_LO Delay in Vcc Gnd out Vcc DRV_LO M2 延迟补偿 Delay compensation GND 在低端驱动器通道上加入延迟时间 Delay is inserted on the fastest path: Low side driver path 去补偿高端延迟 : 脉冲触发器 + 电平转换器和同步整流触发器延迟 to compensate: Pulse trigger + level shifter and SR flip-flop delays. 31

启动电路连接至 V CC Bootstrap connected to Vcc Vcc in in Rboot Vcc Gnd Vcc Gnd out out Dboot Vboot DRV_HI Bridge Vcc DRV_LO GND 硅方案, 高端驱动器电源 Silicon Solution, High Side Driver Supply Cboot CVcc Vcc Vbulk M1 M2 启动步骤 Bootstrap Step: 步骤 1 Step 1 : M2 关闭 M 2 is closed C boot 接地 :C boot 通过 V CC 充电 C boot is grounded: C boot is refueled via V cc. 步骤 2 Step 2: M 1 & M 2 开路 M 1 & M 2 are opened 桥引脚浮动,D boot 阻断, C boot 为浮动区域供电 Bridge pin is floating, D boot is blocked & C boot supplies floating area. 步骤 3 Step 3: M 1 关闭 M 1 is closed 桥引脚转换至大电平, D boot 仍然阻断, C boot 为浮动区域供电 bridge pin moved to bulk level, D boot is still blocked & C boot supplies floating area. 自举电源电路技术用于为高端驱动器供电 Bootstrap technique is used for supplying the high side driver 32

高端驱动器负载电压的根源何在? Root of High Side Driver Negative Voltage? 着重关注半桥支路 Let s focus on the half-bridge branch: 连接至半桥支路的负载是电感型负载 the load connected to a half-bridge branch is inductive: 类似于 LLC 半桥 like an LLC-HB 或者在最简单的情况下是同步降压结构 ( 红色箭头所指的是 MOSFET 体二极管 ) Or with the most simple case in a synchronous buck (where body diodes of the mosfet are represented). Vbulk M1 Dbody1 M2 Dbody2 LLC-HB 33

Vbulk 理论 : 降压转换器工作 Theory: Buck Converter Operation 降压转换器工作的第一阶 1 st step of the buck converter: I L V Bridge M 1 ON I L Time V Bridge V Bulk M 2 OFF Time Step 1: Step: 1 M 1 导通 ON M 2 关闭 OFF 34

Vbulk 理论 : 降压转换器工作 Theory: Buck Converter Operation 降压转换器工作的第二阶 2 nd step of the buck converter: I L M 1 OFF V Bridge Time M 2 OFF I L V Bridge V Bulk -V f Time Step 2: M 1 关闭 OFF M 2 关闭 OFF Step: 1 2 35

Vbulk 理论 : 降压转换器工作 Theory: Buck Converter Operation 降压转换器第三阶 3 rd step of the buck converter: I L M 1 OFF V Bridge Time V Bridge I L V Bulk M 2 ON -V f Time Step 3: Step: 1 2 3 M 1 关闭 OFF M 2 导通 ON 36

Vbulk 理论 : 降压转换器工作 Theory: Buck Converter Operation 降压转换器工作第四阶 4 th step of the buck converter: I L M 1 OFF V Bridge Time V Bridge I L V Bulk M 2 OFF -V f Time Step 4: Step: 1 2 3 4 1 M 1 关闭 OFF M 2 关闭 OFF 37

实际 : 降压转换器工作 Bench: Buck Converter Operation 寄生参数随处可见 Anywhere but in a ppt file there are parasitic elements: 真正的降压转换器 True buck converter: Vbulk 寄生电感 Parasitic inductances M1 Dbody1 寄生电容 Parasitic Capacitors M2 Dbody2 38

实际 : 降压转换器工作 Bench: Buck Converter Operation 降压转换器第一阶 1 st step of the buck converter: Vbulk I L V Bridge M 1 ON I L Time V Bridge V Bulk M 2 OFF Time Step 1: Step: 1 M 1 导通 ON M 2 关闭 OFF 39

实际 : 降压转换器工作 Bench: Buck Converter Operation 降压转换器第二阶 2 nd step of the buck converter: Vbulk I L M 1 OFF V Bridge Time V Bridge I L V Bulk M 2 OFF -V f 31.8V Time Step 2: Step: 1 2 20.0V M 1 关闭 OFF 0V M 2 关闭 OFF -10.0V 1.452846ms 1.453000ms V(BRIDGE) 1.453200ms 1.453400ms Time 40

实际 : 降压转换器工作 Bench: Buck Converter Operation 降压转换器第三阶 3 rd step of the buck converter: Vbulk I L M 1 OFF V Bridge Time V Bridge I L V Bulk M 2 ON -V f Time Step 3: Step: 1 2 3 M 1 关闭 OFF M 2 导通 ON 41

实际 : 降压转换器工作 Bench: Buck Converter Operation 降压转换器第四阶 4 th step of the buck converter: Vbulk I L M 1 OFF V Bridge Time V Bridge I L V Bulk M 2 OFF -V f Time Step 4: Step: 1 2 3 4 1 M 1 关闭 OFF M 2 关闭 OFF 42

实际 : 降压转换器工作 Bench: Buck Converter Operation 桥引脚上的负电压将会在驱动器 IC 内部产生负电流 Negative voltage on bridge pin will create negative current injection inside the IC driver. 浮动区域 Floating area Vbulk VBoot IN_HI Pulse Trigger Level Shifter S R Q Vcc DRV_HI in out M1 V Bridge Gnd Bridge IN_LO Delay in Vcc Gnd out Vcc DRV_LO M2 GND V Bridge < 0 V 时的泄漏通道 Leaky path when V Bridge < 0 V 这泄漏通道可能在驱动器 IC 内部造成一些麻烦 This leakage path could create some trouble inside the driver IC. 43

如何理解负电压? How to Characterize the Negative Voltage? V Bridge V Bulk -V f Time V Bridge 原理 Principle: 桥引脚上增加负脉冲 Negative pulse is added on bridge pin: V neg Time 带可调节负电压 With adjustable Negative voltage 及可调节宽度 And adjustable Width 宽度 Width 负电压在每个脉冲宽度增大, 直至驱动器 IC 失效 At each pulse width the neg. voltage is increased until the driver IC fails. 44

IN_HI IN_LO VCC Sync 1 2 3 4 0 Pulse gen. 如何产生负电压? How the Negative Voltage has Been Created? 驱动器 IC IC Driver D4 MBR1100 10R U1 NCP5106A VCC IN_HI IN_LO GND R4 VBOOT DRV_HI BRIDGE 8 7 6 DRV_LO 5 C11 100n R2 10R Q1 Q2N2907 R3 10R Q2 Q2N2907 R8 47k R9 47k D6 BZX84C18 D5 BZX84C18 Q5 FDP3682 R1 1R Q4 FDP3682 L1 100uH VDC_IN 20V 0 同步降压转换器 Synchronous Buck Converter C3 220uF 50V Rload 10R Vout 0 Rload1 10R 可调节脉冲宽度 Adj. pulse width VCC 1 2 C7 10uF 25V U5 MC33152 D13 C19 D1N4148 100nF D11 D1N4148 C13 100n D14 D1N4148 TX1 R10 47k 0 Q6 FDP3682 D7 BZX84C18 100V 330uF C4 100nF C12 0Vdc to 50V Vneg 可调节负电压 Adj. V Neg 0 负脉冲产生 Negative pulse generation 45

负电压测量示例 Example of Negative Voltage Measurement 桥引脚释放时, 它在高端驱动器上产生一些噪声 When the bridge pin is released, it generates some noise on the hi- side driver. VG_LO (10 V/div) VG_HI (10 V/div) 桥电压引脚 Vbridge pin (20 V/div) V neg = -18 V 注 : 桥引脚电压接近零时施加负电压 Note: Negative voltage pulse is applied when the bridge pin voltage is reaching zero. 宽度 Width = 150 ns 时间 Time (80 ns/div) 46

负电压特征表述 Negative Voltage Characterization Negative pulse voltage (V) 0-5 -10-15 -20-25 -30-35 Negative Voltage versus Neg. pulse duration @ +25 C Negative pulse duration (ns) 0 100 200 300 400 500 600 如果负脉冲在这个区域内, 驱动器将正常工作 If the negative pulse is inside this area, the driver will work properly. 如果负脉冲在这个区域内, 驱动器将不会正常工作或者可能损坏 If the negative pulse is inside this area, the driver will not work properly or can be damaged. 47

负电压温度特征表述 Negative Voltage Characterization in Temperature Negative pulse voltage (V) Negative Voltage versus Neg. pulse duration @ different Temp 0-5 -10-15 -20-25 -30-35 Negative pulse duration (ns) 0 100 200 300 400 500 600-40 C 25 C 125 C 注 : 各颗驱动器 IC 的数据表中将提供这些特征表述 Note: These characterizations will be available in each IC driver datasheet 48

驱动器 IC 评测 Driver IC Remarks 安森美半导体在完整温度范围内 ( 即 -40 < T j <+125 ) 去定义电气参数参见电气参数表或特征曲线 ON Semiconductor defines electrical parameters on overall temperature range (here -40 C <T j < +125 C). See electrical table & characterization curves. 很多竞争对手仅在特定环境温度下 (T amb = +25 ) 去定义电气参数并不总是提供温度特征描绘 Competitors define the electrical parameters only at T amb = +25 C. Temp characterization is not always available 扩展温度范围中最低及最高温度分别是多少? what about min & max over extended temperature range? 很多竞争对手从特征曲线中析取的电气参数值很可能未顾及工艺变化问题 The competitors values extracted from the curves probably do not take into account the lot to lot process variations 变化范围可能较大 the range variation is probably wider. 49

安森美半导体驱动器 IC 相互参照 ON Semiconductor IC Driver Cross Reference Drive trise / tfall typ. (C L =1 nf) Propag. Delay typ. t ON / t OFF Matching Delay Typ / Max Cross Conduction Protection Pin-Out Compatibility Remarks NCP5181 40 ns / 20 ns 100 ns / 100 ns 20 ns / 35 ns - IR2181 IRS2181 3.3 V CMOS/TTL inputs NCP5106A 85 ns / 35 ns 100 ns / 100 ns 20 ns / 35 ns - IR2106 IRS2106, FAN7382 3.3 V CMOS/TTL inputs NCP5106B 85 ns / 35 ns 100 ns / 100 ns 20 ns / 35 ns IR2106 IRS2106, FAN7382 3.3 V CMOS/TTL inputs Internal fixed dead time 100 ns NCP5304 85 ns / 35 ns 100 ns / 100 ns 20 ns / 35 ns IR2304 - IRS2304, L6388/84 FAN7380 3.3 V CMOS/TTL inputs Internal fixed dead time 100 ns NCP5111 85 ns / 35 ns 750 ns / 100 ns 30 ns / 60 ns NA IR2111 IRS2111, 3.3 V CMOS/TTL input Internal fixed dead time 650 ns One pin for creepage NCP5104 85 ns / 35 ns 620 ns / 100 ns 10 ns /45 ns NA IR2104 IRS2104 3.3 V CMOS/TTL input Internal fixed dead time 520 ns 50

采用驱动器变压器的 LLC 半桥电路图 +400 V LLC-HB Schematic with Driver Transformer Vcc R32 33k FF R33 5.6k U5A SFH615-A C11 10n R25 1.8Meg R22 4.7k timer BO NCP1395A R16 75k 1 16 29 R24 250k 2 15 37 R11 160k 38 3 14 C19 10u 4 13 39 R12 150k 5 12 6 C20 10u 1 6 11 R19 5.2k 31 7 10 C14 10n 8 9 C13 100n 15 R15 540 analog ground FF C15 100n 41 Vcc InA R18 1k 42 14 C18 22u R29 47k InB R17 1k 30 12 47k R30 19 Gnd Q1 2N2222 D15 1n5818 Q5 2N2907 Vcc Q2 2N2222 Q6 2N2907 D7 1n5818 C17 0.1u D5 1n5818 D17 1n5818 T2 Q3903-A 20 2.. 5 1 C16 10u 6 21. 3 4 25 22 D8 R10 1N4148 10 34 33 R4 1k D10 1N4148 R20 27 10 32 R21 1k 2 Q10 2N2907 11 23 Q11 2N2907 45 OutA VB OutB Gnd 28 R5 47k 24 R9 47k 17 M1 IRFB11N50A KL195/25,4SW L1 3 26 C7 M2 IRFB11N50A KL195/25,4SW C10 ETD44 ET4415A T1 P = 4W XFMR 5 C1 D4 1N4148 4 8 C8 100p 1 kv 7 Heatsink 18 C/W KL112-25 D12 mbr1645 D3 mbr1645 PCV-0-472-20L L3 int out 4.7uH D11 mbr1645 24 V / 10 A Irms=5 A C3b C3a C2 1mF 1mF 680uF Part number = EEUFC1V681 C3c 1mF D6 Part number = EEUFC1V102 mbr1645 int out R23 10k 0 V R14 10k R1 22k 10 C4 10n R6 10k 13 R2 22k R7 86k LLC 控制器 LLC controller NCP1395 驱动变压器 Driver Transformer C1 22nF Part number = PHE450MB5220JR06 EVOX RIFA 630 V 0.47uF Part number = PHE450MF6470JR06L2 C7 EVOX RIFA 630 V 100uF Part number = 2222-05737101 C10 Snap-in BC Comp. 450 V L1 PCV-0-274-04 220u U5B SFH615-A U2 TL431 40 16 C6 470p C5 470p 18 R3 22k R8 10k 规格为 24 V @ 10 A 的 LLC 半桥 LLC-HB with 24 V @ 10 A NCP1395, 带双 DRV 输出的 LLC 控制器 the LLC controller with dual DRV outputs. 变压器驱动 LLC 转换器的 MOSFET Transformer drivers the MOSFETs of LLC converter. 52

采用驱动器 IC 的 LLC 半桥电路图 +400 V LLC-HB Schematic with Driver IC R32 33k FF R33 5.6k U5A SFH615-A C11 10n R25 1.8Meg R22 4.7k timer BO NCP1395A R16 75k 1 16 29 R24 250k 2 15 37 R11 160k 38 3 14 C19 10u 4 13 39 R12 150k 5 12 6 C20 10u 1 6 11 R19 5.2k 31 7 10 C14 10n 8 9 C13 100n 15 R15 540 analog ground FF C15 100n 41 35 Vcc InA 42 14 R28 47k C18 22u R31 47k InB 30 12 Gnd 25 D1 R13 1N4937 10 U1 NCP5181 1 8 36 2 7 44 3 6 51 4 5 C12 100n C9 100nF R26 OutA 10 2 D2 1N4148 VB 11 R27 OutB 10 23 D9 1N4148 Gnd 45 28 R5 47k 24 R9 47k 17 M1 IRFB11N50A KL195/25,4SW L1 3 26 C7 M2 IRFB11N50A KL195/25,4SW C10 ETD44 ET4415A T1 P = 4W XFMR 5 C1 D4 1N4148 4 8 C8 100p 1 kv 7 Heatsink 18 C/W KL112-25 D12 mbr1645 D3 mbr1645 PCV-0-472-20L L3 int out 4.7uH D11 mbr1645 24 V / 10 A Irms=5 A C3b C3a C2 1mF 1mF 680uF Part number = EEUFC1V681 C3c 1mF D6 Part number = EEUFC1V102 mbr1645 int out R23 10k 0 V R14 10k R1 22k 10 C4 10n R6 10k 13 R2 22k R7 86k LLC 控制器 LLC controller NCP1395 驱动器 IC Driver IC NCP5181 C1 22nF Part number = PHE450MB5220JR06 EVOX RIFA 630 V 0.47uF Part number = PHE450MF6470JR06L2 C7 EVOX RIFA 630 V 100uF Part number = 2222-05737101 C10 Snap-in BC Comp. 450 V L1 PCV-0-274-04 220u U5B SFH615-A U2 TL431 40 16 C6 470p C5 470p 18 R3 22k R8 10k 规格为 24 V @ 10 A 的 LLC 半桥 LLC-HB with 24 V @ 10 A NCP1395, 带双 DRV 输出的 LLC 控制器 the LLC controller with dual DRV outputs. NCP5181, 驱动器 IC 驱动 LLC 转换器的 MOSFET driver IC drives the MOSFETs of LLC converter. 53

V GS 波形 V GS Waveform 2 µs / div V GS_ML (5 V/div) V GS_MU (5 V/div) I MU (2 A/div) V DS_ML (100 V/div) 驱动变压器 Driver transformer 驱动器 IC Driver IC (NCP5181) 波形看上去类似 The waveforms seem similar. 54

高端 MOSFET 关闭 High side MOSFET Turns off 关闭比较 Turn-off comparison 80 ns / div V GS_ML (5 V/div) V GS_MU (5 V/div) I MU (2 A/div) V DS_ML (100 V/div) 驱动变压器 Driver transformer 驱动器 IC Driver IC (NCP5181) 驱动器 IC 更有力地关闭 MOSFET The driver IC turns off the MOSFETs more vigorously. 驱动器 IC 关闭 MOSFET 时快 70 ns, 降低开关损耗 IC turn-off is 70 ns faster, lowering the switching losses 55

高端 MOSFET 导通 High side MOSFET Turns on Turn-on comparison 200 ns / div V GS_ML (5 V/div) V GS_MU (5 V/div) I MU (2 A/div) V DS_ML (100 V/div) 驱动变压器 Driver transformer 驱动器 IC Driver IC (NCP5181) 驱动器 IC 在高端与低端 MOSFET 之间保持安全及足够的死区时间 The driver IC keeps safe and enough dead time between high and low side MOSFETs. 56

能效比较 The Efficiency Comparison 驱动器 IC Driver IC 驱动变压器 Driver Transformer 输入功率 Input power 输出功率 Output power 输出电压 Vout 输出电流 Iout 能效 η (W) (W) (V) (A) 128.33 119.72 23.96 5.00 93.29% 257.2 235.46 23.57 9.99 91.55% 128.34 119.72 23.96 5.00 93.29% 258.5 236.46 23.67 9.99 91.48% IC 驱动器与变压器方案的能效没有显著区别 There is no efficiency difference between the IC driver and transformer solutions. 57

总结 : 变压器还是 IC? Summary: Transformer or IC? 如果精心设计, 两种方案都可以 Both solutions work if well-trimmed. 我们建议采用驱动器 IC 的理由 We recommend the IC solution because: 我们不卖变压器 We don t sell the transformer. 变压器需要手动插入 Manual insertion for the transformer. 简化布线 Ease the layout 简化设计 Ease the design 免除诸多变压器问题, 如 Free of transformer problems, e.g.: 隔离被破坏 isolation is destroyed, 磁通走散 flux walking away, 关闭后未预料到的振铃 unexpected ringing after turn off, 低高度电源中变压器的高度是个问题 Height of the transformer in low profile PSU 59

For More Information View the extensive portfolio of power management products from ON Semiconductor at www.onsemi.com View reference designs, design notes, and other material supporting the design of highly efficient power supplies at www.onsemi.com/powersupplies 60