- 您现在的位置：买卖IC网 > PDF目录17381 > ADP1829-EVALZ (Analog Devices Inc)BOARD EVALUATION ADP1829 PDF资料下载
参数资料
| 型号： | ADP1829-EVALZ |
| 厂商： | Analog Devices Inc |
| 文件页数： | 17/28页 |
| 文件大小： | 0K |
| 描述： | BOARD EVALUATION ADP1829 |
| 标准包装： | 1 |
| 主要目的： | DC/DC，步降 |
| 输出及类型： | 2，非隔离 |
| 输出电压： | 1.2V，1.8V |
| 电流 - 输出： | 15A，15A |
| 输入电压： | 5.5 ~ 18 V |
| 稳压器拓扑结构： | 降压 |
| 频率 - 开关： | 300kHz |
| 板类型： | 完全填充 |
| 已供物品： | 板 |
| 已用 IC / 零件： | ADP1829 |
| 相关产品： | ADP1829ACPZ-R7DKR-ND - IC REG CTRLR BUCK PWM VM 32LFCSP ADP1829ACPZ-R7CT-ND - IC REG CTRLR BUCK PWM VM 32LFCSP ADP1829ACPZ-R7TR-ND - IC REG CTRLR BUCK PWM VM 32LFCSP |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页第14页第15页第16页当前第17页第18页第19页第20页第21页第22页第23页第24页第25页第26页第27页第28页
Data Sheet
In the case of output capacitors where the impedance of the
ADP1829
Furthermore, the high-side MOSFET transition loss is
? V OUT ≈
? I L
V IN I L ( t R + t F ) f SW
P T ≈
ESR and ESL are small at the switching frequency, for instance,
where the output capacitor is a bank of parallel MLCC capacitors,
the capacitive impedance dominates and the ripple equation
reduces to
(7)
8 C OUT f SW
Make sure that the ripple current rating of the output capacitors
is greater than the maximum inductor ripple current.
During a load step transient on the output, the output capacitor
supplies the load until the control loop has a chance to ramp the
inductor current. This initial output voltage deviation due to a
approximated by the equation
2
where t R and t F are the rise and fall times of the selected
MOSFET as stated in the MOSFET data sheet.
The total power dissipation of the high-side MOSFET is the
sum of the previous losses.
P D = P C + P G + P T
where P D is the total high-side MOSFET power loss. This
dissipation heats the high-side MOSFET.
(10)
(11)
P C ≈ I L 2 R DSON
V OUT
V
P LS ≈ I L 2 R DSON ? 1 ? OUT
?
(14)
V IN
?
?
change in load is dependent on the output capacitor characteristics.
Again, usually the capacitor ESR dominates this response, and
the ΔV OUT in Equation 6 can be used with the load step current
value for ΔI L .
SELECTING THE MOSFETS
The choice of MOSFET directly affects the dc-to-dc converter
performance. The MOSFET must have low on resistance
(R DSON ) to reduce I 2 R losses and low gate-charge to reduce
switching losses. In addition, the MOSFET must have low
thermal resistance to ensure that the power dissipated in the
MOSFET does not result in overheating.
The power switch, or high-side MOSFET, carries the load
current during the PWM on-time, carries the transition loss of
the switching behavior, and requires gate charge drive to switch.
Typically, the smaller the MOSFET R DSON , the higher the gate
charge and vice versa. Therefore, it is important to choose a
high-side MOSFET that balances those two losses. The conduction
loss of the high-side MOSFET is determined by the equation
(8)
V IN
where:
P C is the conduction power loss.
R DSON is the MOSFET on resistance.
The gate charge losses are dissipated by the ADP1829 regulator
and gate drivers and affect the efficiency of the system. The gate
charge loss is approximated by the equation
P G ≈ V IN Q G f SW (9)
where:
P G is the gate charge power.
Q G is the MOSFET total gate charge.
f SW is the converter switching frequency.
Making the conduction losses balance the gate charge losses
usually yields the most efficient choice.
The conduction losses may need an adjustment to account for
the MOSFET R DSON variation with temperature. Note that
MOSFET R DSON increases with increasing temperature. The
MOSFET data sheet should list the thermal resistance of the
package, θ JA , along with a normalized curve of the temperature
coefficient of the R DSON . For the power dissipation estimated in
Equation 11, calculate the MOSFET junction temperature rise
over the ambient temperature of interest.
T J = T A + θ JA P D (12)
Then calculate the new R DSON from the temperature coefficient
curve and the R DSON specification at 25°C. A typical value of the
temperature coefficient (TC) of the R DSON is 0.004/°C, so an
alternate method to calculate the MOSFET R DSON at a second
temperature, T J , is
R DSON @ T J = R DSON @ 25 ° C [ 1 + TC ( T J ? 25 ° C )] (13)
Then the conduction losses can be recalculated and the
procedure iterated once or twice until the junction temperature
calculations are relatively consistent.
The synchronous rectifier, or low-side MOSFET, carries the
inductor current when the high-side MOSFET is off. For high
input voltage and low output voltage, the low-side MOSFET
carries the current most of the time, and therefore, to achieve
high efficiency, it is critical to optimize the low-side MOSFET
for small on resistance. In cases where the power loss exceeds
the MOSFET rating, or lower resistance is required than is
available in a single MOSFET, connect multiple low-side
MOSFETs in parallel. The equation for low-side MOSFET
power loss is
? ?
? ?
where:
P LS is the low-side MOSFET on resistance.
R DSON is the parallel combination of the resistances of the low-
side MOSFETs.
Check the gate charge losses of the synchronous rectifier(s)
using the P G equation (Equation 9) to be sure they are
reasonable.
Rev. C | Page 17 of 28
相关PDF资料 |
PDF描述 |
|---|---|
| R1S-1515/P-R | CONV DC/DC 1W 15VIN 15VOUT |
| ADP2102-1.8-EVALZ | BOARD EVAL FOR ADP2102-1.8 |
| ECM10DCMD-S288 | CONN EDGECARD 20POS .156 EXTEND |
| ADP2102-1.875EVALZ | BOARD EVAL FOR ADP2102-1.875 |
| 195D685X0016X2T | CAP TANT 6.8UF 16V 20% 2910 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| ADP1850 | 制造商:AD 制造商全称:Analog Devices 功能描述:Wide Range Input, Dual/Two-Phase, DC-to-DC Synchronous Buck Controller |
| ADP1850ACPZ | 制造商:Analog Devices 功能描述:IC BUCK CNTRL SYNC 2PH 32LFCSP |
| ADP1850ACPZ-R7 | 功能描述:IC REG CTRLR BUCK PWM CM 32LFCSP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 特色产品:LM3753/54 Scalable 2-Phase Synchronous Buck Controllers 标准包装:1 系列:PowerWise® PWM 型:电压模式 输出数:1 频率 - 最大:1MHz 占空比:81% 电源电压:4.5 V ~ 18 V 降压:是 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-5°C ~ 125°C 封装/外壳:32-WFQFN 裸露焊盘 包装:Digi-Reel® 产品目录页面:1303 (CN2011-ZH PDF) 其它名称:LM3754SQDKR |
| ADP1850DP-EVALZ | 功能描述:EVAL BOARD FOR ADP1850DP RoHS:是 类别:编程器，开发系统 >> 评估板 - DC/DC 与 AC/DC（离线）SMPS 系列:- 标准包装:1 系列:- 主要目的:DC/DC，步降 输出及类型:1，非隔离 功率 - 输出:- 输出电压:3.3V 电流 - 输出:3A 输入电压:4.5 V ~ 28 V 稳压器拓扑结构:降压 频率 - 开关:250kHz 板类型:完全填充 已供物品:板 已用 IC / 零件:L7981 其它名称:497-12113STEVAL-ISA094V1-ND |
| ADP1850SP-EVALZ | 功能描述:EVAL BOARD FOR ADP1850SP RoHS:是 类别:编程器，开发系统 >> 评估板 - DC/DC 与 AC/DC（离线）SMPS 系列:- 产品培训模块:Obsolescence Mitigation Program 标准包装:1 系列:True Shutdown™ 主要目的:DC/DC，步升 输出及类型:1，非隔离 功率 - 输出:- 输出电压:- 电流 - 输出:1A 输入电压:2.5 V ~ 5.5 V 稳压器拓扑结构:升压 频率 - 开关:3MHz 板类型:完全填充 已供物品:板 已用 IC / 零件:MAX8969 |
发布紧急采购，3分钟左右您将得到回复。