The technology of * Silent Switcher that already won patent achieved your person’s impressive EMI performance in power supply of high frequency, high power. As next generation of this technology, silent Switcher 2 simplified to circuit board is designed and be made, the method that its adopt is bring into capacitor of hot annulus road in enclose, PCB layout is accordingly dinky to the influence of EMI.

 

Manostat of Silent Switcher 2 is SOC power supply

 

Current (reach future) what use on car piece inside system (SOC) parts of an apparatus and the place that before a few acting congener products have what likeness hardly. The rate that the exponential sex of the character of information entertainment system and car security system and function raises pressing requirement SOC to process data raises level of a few amounts than in the past, the high resolution that includes to come from many signal source with few defer processing inspects frequency data. For example, of if car before buy photographs “ resembling a head to see ” some kind is dangerous, criterion car must make immediately answer, or reminds attention of the person that drive, or brake apply the brake. To satisfy newest computational requirement, SOC is enclosed in its in compositive parts of an apparatus of more and more high cost report, but, how will provide these needs power? In the car, power carries plan to must be had efficient, compact the characteristic with low EMI. The requirement that SOC raises makes they more satisfy hard.

 

For instance, a R-Car H3 SOC contains 8 ARM kernel, DSP, video and graphical processor, and additional supportive parts of an apparatus. All these component all need reliable power supply, the power source course that includes 3 to be used at peripheral and subcomponent (two 5V, 3.3V and 1.8V) , power source track that are used at DDR3 and LPDDR4 (the 1.2V and 1.1V) , power source track that is used at the kernel with another (0.8V) .

 

The electric running water that needs to support SOC place is smooth, the controller of switch power source that has exterior MOSFET is precede over sheet piece the tradition of parts of an apparatus of type power source chooses plan. Odd a type parts of an apparatus because utmost of its interior MOSFET is cut dimension of cost and solution and conspicuous, but the hot problem that they get bounds voltaic ability and existence on the tradition restricted his to use normally. LT8650S and a new sheet piece the voltaic capacity that series of manostat of type step-down Silent Swicther has supportive SOC and heat management are characteristic.

 

Because have efficient manage character with heat, because of this Power By Linear™The capacity of output electric current of LT®8650S, LT8609S and LT8645S is onlier than the model a type manostat is tall much. 3V was the input voltage limits of 65V) to cover all sorts of n requirements of car batteries to LT8645S to 42V (. These sheet piece type IC has compositive MOSFET, can move with the frequency of prep above 2MHz, consequently cut solution dimension and cost, AM frequency kept away from in the meantime paragraph. Silent Switcher manostat reduces EMI for utmost only and design, make its make a kind of when suit SOC popular choice thereby.

 

Double output: 5V/4A and 1V/4A

 

Graph 1 show gave a double output (2MHz 5V/4A and 1V/4A) solution, its used two channels of LT8650S. This circuit can make easily modification be combined in order to suit other output, include such as 3.3V and 1.8V or 3.3V and 1.1V to wait, in order to use the wide input range of LT8650S. LT8650S still can use as converter of the first class, those who be used at offerring more output is follow after all sorts of inferior power manostat of switch of the 2nd class or LDO manostat.

 

Graph 1: Use LT8650S the double output of two passageways (5V/4A and 1.0V/4A) solution

 

LT8650S used the design of Silent Switcher 2 that can eliminate EMI, have capacitor of compositive hot annulus road, aim utmost reduces noise antenna size. Union is compositive change MOSFET, this achieved unusually superior EMI performance.

 

Graph 2: Suit solution of the 4 photographs of SOC application, 3.3V/16A, 2MHz

 

Apply to the 16A solution of SOC

 

Graph 2 show the 3.3V/16A that went out to be used at providing SOC power source, 4 photographs solution. Graph 3 show gave radiation EMI to check a result.

 

Graph 3: The graph shows the radiation EMI of the solution 2 times to check a result

 

Additional, car SOC returns noise of laden to power source transient state is due extremely high demand. The rate of load current changeover of peripheral power source reachs power supply of 100A/µs (kernel taller) the circumstance is not scarce. No matter laden metabolic circumstance how, power source must utmost reduces output voltage twinkling to change. Sudden switch frequency (for instance LT8650S series can achieve 2MHz) to conduce to accelerate twinkling to change resumptive rate. Using circumstance of compensatory of correct annulus road to fall, faster switch frequency correspondence is answered at faster trends. Graph the 2 component that gave out to suit are worth. It is in circuit board layout, answer to reduce the output capacitor from circuit as far as possible to come to walk along line inductance ladenly, this also are most important. Graph 4 gave out to pursue 2 transient state that show a solution check a result.

 

Graph 4: The graph shows the laden transient state of the solution 2 times to answer

 

What apply in the light of inferior power is efficient, compact model solution

 

Besides application of the low voltage such as such as SOC and CPU, tall electric current, car and other vehicle still need to be used at the power source of load of numerous small electric current, for example: Net of couplet of dashboard, head-up display, car (charger of V2X) , sensor, USB, etc.

 

Because can use space and batteries n to suffer,be restricted, accordingly to power source converter, efficient with small solution dimension is the most significant demand. Low noise is premise condition. LT8609S is one is aimed at all appropriate solutions of these application. This parts of an apparatus designed the 3V that is aimed at car batteries condition to input voltage limits to 42V. Compositive MOSFET, inside the compensates circuit and 2MHz working frequency utmost of buy reduced LT8609S solution size. Technology of Silent Switcher 2 and collect were applied to shape in LT8609S capacitor of hot annulus road, with the ground reduces noise n and providing exceedingly good efficiency index and outstanding EMI performance as far as possible. Graph 5 show the 2MHz that went out to use LT8609S, 5V/2A application.

 

Graph 5: Use the 2MHz 5V/2A application of LT8609S

 

Graph 6 show went out to find a place for the complete LT8609S manostat on two circuit board. The collect of LT8609S shapes MOSFET and inside buy compensation circuit reduces package number to be mixed for itself of parts of an apparatus a few exterior component. Plus frequency of high speed switch, total size is the core solution of this representative application only 11.5mm X 12.3mm.

 

Graph 6: LT8609S the small solution of two circuit board dimension

 

A kind of method that reduces solution cost is the PCB number of plies that reduces place to need as far as possible, but this need is cost with sacrificial function is to be able to expect. For example, the EMI performance that achieves with respect to place, two circuit board the solution predicts solution and 4 circuit board is incoordinate. Graph 7 medium EMI tests show as a result: The LT8609S that uses two circuit board can satisfy radiate of CISPR 25 Class 5 EMI to limit a demand. Undertook comparative to using the EMI property of the equivalent solution of layer and 4 two circuit board.

 

Graph 7: (The test showed the average radiate EMI that A) uses a LT8609S of two circuit board to be in as a result the with reducing EMI further circumstance when enabling function of modulation of patulous spectrum frequency. (B) is mixed of two of LT8609S the function of EMI of peak value radiate of 4 circuit board is compared.

 

Generally speaking, technology of Silent Switcher 2 is using two even monolayer circuit board admirable EMI property is acquired below the circumstance, can reduce production cost greatly consequently.

 

When the circuit board number of plies that should use is less, hot property is the problem of a concern letting a person normally, but the circumstance when using LT8609S is not such. The low noise n of technology of Silent Switcher 2 and efficient the power loss that had advantage is switch changeover generation is very small. This and increase model medicinal powder heat encloses photograph union, make LT8609S shows the hot performance of person giving arrogant. Graph 8 show gave the hot property contrast between two circuit board and 4 circuit board. See by the graph, to 12V batteries input, LT8609S issues the temperature rise difference when the job to be less than 11°C in full laden condition.

 

Graph 8: Of two of LT8609S the hot property with 4 circuit board is compared.

 

Face the solution of Silent Switcher 2 of 48V car system

 

Traditional car uses 12V batteries to feel ignition, illume, frequency and equipment of information recreation electron, safe power supply of system of functional device etc. Unfortunate is, the power supply ability of 12V car system is in by limitation 3kW, and the car electron product with huge amount to this the challenge that “ bounds ” launchs increasingly grow in quantity.

 

This problem, mix plus electric car drive automatically systematic occurrence, carried a standard to pose a challenge to power, automobile industry will get lost 48V batteries power source to serve as a kind of solution subsequently. Compare with photograph of 12V electrical system, 48V electrical system is in power demand can reduce distribution loss below very high case, improve integral efficiency thereby.

 

In 48V system, the challenge that poses to DC/DC converter is indispensible the changeover efficiency that keeps as similar as 12V system, dimension and low EMI, and right now, tall step-down is compared make of these norms index it is more difficult to satisfy. Do not answer to be lost for nothing in DC/DC transition by the profit that uses generation of 48V batteries power source. Can move to disturb AM frequency in order to avoid with 2MHz frequency paragraph odd manostat suits a formula switch very much 48V car electrical system, want them to accomplish this can efficiently to go only.

 

Can accept 48V nominal the sheet of the input piece amount of type step-down manostat is limited, they support the load current that is less than 5A mostly. LT8645S is odd a type step-down manostat can rely on the input voltage that is as high as 65V to support 8A load. Of its 40ns the shortest put through time (TON) and fast and clean switch edge (graph 9) can realize tall switch frequency and efficient (94%) is as high as when 2MHz.

 

Graph 9: Odd parts of an apparatus uses a type Silent Switcher MOSFET driver design, can produce fast, clean switch edge. This came true efficient, although be in,circumstance of high frequency operation falls not exceptional also. Additional, the driver of innovation returned utmost to had decreased to rush, restrained ringing, and a source that when introducing other drive, these will become generation EMI.

 

Compositive changed compensation circuit and by-pass capacitor utmost to reduce overall solution size, simplified low EMI layout. Use a simple ferrite magnetism bead filter, LT8645S can adopt restriction of norms of CISPR 25 Class 5 EMI, stay abundant is spent.

 

Graph 10 show those who went out to use LT8645S to exceed low EMI 2MHz, 5V/8A application. Graph 11 show the efficiency that gave LT8645S, graph 12 showed LT8645S solution measure.

 

Graph 10: Use LT8645S exceed application of low EMI 5V/8A

 

Graph 11: Use at should exceeding the LT8645S efficiency when low EMI solution

 

 

Graph 12: The small solution that LT8645S demonstrates circuit dimension

 

LT8645S has the extraordinary capacity that supports tall step-down to compare, be when the job even when tall switch frequency also is such, this profit from of its 40ns the shortest put through time. For example, LT8645S can be as high as the input of 30V to generate 1.8V output from below 1MHz switch frequency. If had jumped,certain switch cycle can be accepted, so the input can lift the absolutely the biggest rating to 65V.

 

Should output under 3.1V when, the exterior power source that the BIAS of LT8645S quotes a foot to should join to 3.1V of a prep above in order to improve efficiency. If do not have such power source to be able to be used, bring BIAS the foot to join to GND. Graph 13 show went out to be able to input twinkling to change in 65V the 1MHz 1.8V/8A solution that works normally below the circumstance.

 

Graph 13: The circuit of 1MHz 1.8V/8A application that uses LT8645S can bear the input twinkling that is as high as 65V changes

 

Besides low EMI, can come true below high frequency condition efficient, have wide input besides voltage limits, the characteristic of LT8645S still includes to exceed electric current of small static state and low-pressure difference. Below unused condition, exceed small static electric current to be able to extend batteries run time. It is most important that low-pressure wrong character moves a circumstance to fall to be run continuously to be being sent in cold car.

 

Conclusion

 

Silent Switcher and manostat of Silent Switcher 2 can satisfy the EMI radiate requirement with car harsh environment. Watch requesting an audience the Silent Switcher parts of an apparatus of 1 enumerate, include a few products of article introduction among them.

 

In the parts of an apparatus that emphasizes the introduction in the article, synchronism of LT8650S double passageway is odd a manostat of type Silent Switcher 2 provided limits of wide input voltage, superior EMI performance and small solution measure for SOC application, still can offer output of many tall electric current and swift transient state to answer at the same time. LT8609S synchronism is odd manostat offerred a type Silent Switcher 2 electric current of limits of wide input voltage, small static state, outstanding EMI performance, small solution size and efficient, this parts of an apparatus can satisfy the requirement of the power source system that the nowhere in current car is absent easily. LT8645S (input can be formed to 65V) those who suit 48V car system is compact model low EMI solution.

 

Express 1. Low EMI Silent Switcher and synchronous step-down of Silent Switcher 2 (“S”) manostat. Outstanding to was being done in the parts of an apparatus of the description in the article show.

 

 

Annotate

 

* Silent Switcher is the technology that obtains patent authorization, patent date is 8823345.