【正文】 閉。 mode Iref is not acting as the sole current limitation level。 fast transient and lowcurrent/lowpower LEDs, where power efficiency is not an issue。 into account the variability of parasitic capacitors and inductors, 設(shè)計(jì)已經(jīng)考慮到可變性的寄生電容和電感 , as well as of the load and all processvoltagetemperature (PVT) 以及負(fù)載和所有過(guò)程電壓溫度 (PVT)的部分。 The output current slope during the turnon phase of the load 文獻(xiàn)翻譯 021309208 吳驍奕 depends on how fast that power MOS is switched ON. 輸出電流斜率在開(kāi)機(jī)階段的負(fù)載取決于 MOS的開(kāi)關(guān)開(kāi)啟的速度。 generated by an onchip bandgap circuit. The programmability of the Current Slope Control allows the employment of the smart driver with different LEDs configuration, in order to keep down the ringing. 這個(gè)可編程的電流升降控制允許使用的智能與不同的發(fā)光二極管驅(qū)動(dòng)配置 ,為了降低偏振。 strategy is a particular way of using the current control loop in Fig. 4 and the control logic acting on the MB and the power MOS transistors not for power efficiency issues, but to face inrush 因此 ,軟啟動(dòng)方式是一種特定的方式來(lái)使用該電流控制回路，在圖 4控制邏輯作用于 MB金屬氧化物半導(dǎo)體晶體管的能量不是功率效率問(wèn)題 ， currents during fast turnon LED transients. The drawback 但需要面對(duì)快速瞬變電流刺激的涌入。 Finally, the device presents a low power absorption, a feature extremely important for a LED driver IC. As shown in Table I, 最后 ,該設(shè)備提供了一個(gè)低功率吸收的一個(gè)功能非常重要的 LED驅(qū)動(dòng)文獻(xiàn)翻譯 021309208 吳驍奕 集成電路。 phase. In experimental measures with 12 and 14V batteries, Vref set to , and 1A load, the power consumption is limited to over 12W and 14W, respectively (., the measured 在實(shí)驗(yàn)時(shí)候用 12和 14 伏特的電池 ,Vref設(shè)置為 伏特 ,一個(gè) 1安培的負(fù)荷 ,功率消耗是限制分別在 12瓦特和 14瓦特。 was found between increased area of the power MOS and reduction of its onresistance and hence of the power consumption. 關(guān)掉被發(fā)現(xiàn)增加了區(qū)域之間 MOS以及減少電阻，因此增加了功率消耗。 and with slope current control enabled [see Fig. 10(b)] when the load is the series of three with only 50mA forward 和升降電流控制時(shí)使當(dāng)負(fù)載是三個(gè) led燈串聯(lián)時(shí)只有 50毫安文獻(xiàn)翻譯 021309208 吳驍奕 的正向偏壓。 V. CONCLUSION 六 .小結(jié) The letter presented the design and experimental characterization of a smart driver for LED automotive applications. The 這文章提出智能驅(qū)動(dòng) LED汽車(chē)應(yīng)用設(shè)計(jì)和實(shí) 驗(yàn)特征。 。 characterization with LEDs of different power levelsand with different types of connections is also discussed. 對(duì) 二極管 不同的電壓等級(jí)和不同的連接方式的實(shí)驗(yàn)特征也做了討論。 current control of the proposed LED driver [see Fig. 10(b)]. To 這些不會(huì)發(fā)生歸功于 LED驅(qū)動(dòng)程序的電流升降控制。 were measured and then the extracted parasitic ponents, see 真實(shí)汽車(chē)電纜用于測(cè)量 ,然后提取寄生元件 ,從表格 2可以看出，被用于以下測(cè)量值。 文獻(xiàn)翻譯 021309208 吳驍奕 Fig. 4. Hence, with 1A load current the power consumption of the driver would be roughly and, considering a 12V battery system, this leads to a maximum power efficiency of 因此 ,如果負(fù)載電流的功率消耗的驅(qū)動(dòng)都是大概在 ,考慮一個(gè)12伏特電池系統(tǒng) , 這令最大的功率效率為 95%. 95%. The smart power IC in Fig. 4 can sustain voltage from –15 to 55V and temperature from –40 to 150 ?C. It has an area 在圖四中的智能功率集成電路可以維持電壓從 15伏特到 55伏特，溫度從 40攝氏度到攝氏度。 TABLE I POWER PERFORMANCE OF THE PROPOSED SMART DRIVER 表格 1 智能驅(qū)動(dòng)的動(dòng)力性能 TABLE II WIRING PARASITIC ESTIMATION 表格 2 寄生接線的估算 MOS is almost negligible during turn OFF and power down phases, and it is very low even during the turn ON of the load, with a maximum of while driving a 1A load. MOS在關(guān)掉電源中斷階段是幾乎可以忽略不 ,即使它是在打開(kāi)的負(fù)載情況下也是非常低的，大概最大在 微瓦當(dāng)帶一個(gè)負(fù)載的時(shí)候。為達(dá)此目的 ,過(guò)熱保護(hù) ,使用芯片上的溫度傳感器。 the output current lasts over a configurable current limit for more than a configurable lapse of time, a Soft Start strategy is 當(dāng)輸出電流持續(xù)超過(guò)一個(gè)可配置一段時(shí)間的電流限制時(shí) ,一個(gè)軟啟動(dòng)策略將被采用， adopted, switching the load by modulating the duty cycle and the frequency (., Ton and Toff ) parameters and hence controlling 文獻(xiàn)翻譯 021309208 吳驍奕 the length of the turnon phase. 開(kāi)關(guān)負(fù)載的調(diào)制周期頻率頻率 (即 T開(kāi)和 T關(guān) )參數(shù) ,從而控制開(kāi)機(jī)階段的 相位。轉(zhuǎn)換速率可以控制通過(guò)調(diào)整控制它的轉(zhuǎn)換速度 ,可以控制負(fù)載電流晶體管的尺寸組成 OTA(固定模式實(shí)現(xiàn)在 [12])或通過(guò)調(diào)節(jié)其偏置電流 。 of the voltage regulation loop in Fig. 4 changes in a relevantway. As a consequence, the susceptibility to instability of the overall 因此， circuit varies, along with the entity of the ringing, as illustrated 不穩(wěn)定的磁感系數(shù)的整體電路的變化 ,隨著實(shí)體振蕩，在圖 7中闡述的那樣。 The driving of a LED calls also for specific strategies to avoid the ringing phenomenon on the connecting wire with the consequent current overshoot. The Soft Start and Current 發(fā)光二極管的驅(qū)動(dòng)也要求具體策略在連接線上避免振蕩現(xiàn)象與隨之產(chǎn)生的電流超調(diào)。檢測(cè)過(guò)流現(xiàn)象是被運(yùn)用于過(guò)壓過(guò)流檢測(cè)塊 ,如圖 4所示。 文獻(xiàn)翻譯 021309208 吳驍奕 than normal operating currents: the power MOS is no directly driven by the OTA and the bined action of the current loop control and of the control logic on the MOS MB determines the Ton and Toff periods (and hence the switching duty cycle and frequency) of the power MOS. To be noted that in switching 電源 MOS沒(méi)有直接被 OTA和聯(lián)合作用 的電流環(huán)路控制。 mode with duty cycle and frequency depending on the Ton and Toff times set by the control logic. Summarizing, in linear regulator mode Iref is configured so that the current loop control is activated only for output currents of several amperes, much higher than the operating load currents 總結(jié) ,在線性調(diào)節(jié)器模式 Iref是如此配置的為了電流環(huán)路控制輸出電流只有安培。 Iref drives the gate of MOS MB : if Imir is lower than Iref , then Imir和 Iref之間的在 MOS驅(qū)動(dòng)上的區(qū)別是：如果 Imir低于 Irel，那么MB是關(guān)閉的 MB is OFF and the power MOS, driven