- 您现在的位置：买卖IC网 > PDF目录43901 > L7250 (STMICROELECTRONICS) VOICE COIL MOTOR CONTROLLER, PQFP64 PDF资料下载
参数资料
| 型号： | L7250 |
| 厂商： | STMICROELECTRONICS |
| 元件分类： | 运动控制电子 |
| 英文描述： | VOICE COIL MOTOR CONTROLLER, PQFP64 |
| 封装： | TQFP-64 |
| 文件页数： | 33/46页 |
| 文件大小： | 478K |
| 代理商： | L7250 |
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页第29页第30页第31页第32页当前第33页第34页第35页第36页第37页第38页第39页第40页第41页第42页第43页第44页第45页第46页
39/46
L7250
4.3 Negative Voltage Regulator (flyback configuration)
This is the default Negative Voltage Regulator configuration; programming the Test Register is possible to re-
configurate this regulator following the indication present on the next paragraph.
The negative voltage regulator is a fixed frequency switcher intended to provide bias for the MR head preamp.
The NVR consists of an internal triangular wave oscillator, an error amplifier, a comparator and a circuitry to soft
start_up the regulator itself, in conjunction with an external PMOS power device, power diode, inductor, capac-
itor, feedback resistors and compensation network (refer to the block diagram of the negative voltage regulator
including also the external components).
The error amp compares the external voltage feedback to the internal reference (Vbg = 1.25V). The voltage dif-
ference value is scaled by two external resistors. The ratio of these two resistors determines the nominal value
of the regulated negative voltage (the internal reference is set to the bandgap voltage ~1.25V). The error am-
plifier input is available at N_FEED pin and the amplifier output is available at N_COMP pin. The voltage error
gain and the loop compensation can be adjusted by the external components across these two pins. The output
of the error amplifier is compared to an internal triangular wave oscillator to determine the duty cycle of the ex-
ternal PMOS power switch. A voltage clamp is placed on the error amplifier output to limit the maximum duty
cycle. The nominal value of the triangular wave oscillator frequency is 500 kHz (programming the test register
Reg 0FH to ‘00001001’ it is possible to increment the switching frequency to the nominal value of 1Mhz). During
the ON portion of the duty cycle, the PMOS charges an external inductor. During the OFF phase, the inductor
charges a capacitor through an external diode, in a voltage inverter configuration. This architecture avoids any
negative voltage on the L7250 IC pins. Under normal specified load conditions and correct scaling of the ex-
ternal components the regulator circuit should operates in a constant frequency variable duty cycle switch mode
without any cycle slips. The NVR include also a digital soft start_up circuitry in order to limit the in rush current
coming from the power supply when the regulator is turned-on. The NVR is controlled via serial port (using the
Reg. 05H -> b1 the regulator could be turned on and off). During the power-up and power-down phases the
regulator is always off being the serial port in reset status then the VnegEn bit equal to zero. During those phas-
es the N_DRV output driver is in tri-state condition then an external pull-up to assure the Pch off condition must
be considered.
Figure 17. Negative regulator (Flyback configuration) - default configuration
12
N_ C O M P
10
N_ DR V
V CC5
21
V R EF 25
Vbg
(typ 1.2 5)
11
N_ F E ED
R1e x t
M1 ex t
R 2e x t
Rc ex t
Cc ex t
Cfe xt
500Khz - 1Mhz
5K
相关PDF资料 |
PDF描述 |
|---|---|
| L7980A | 3.5 A SWITCHING REGULATOR, 1000 kHz SWITCHING FREQ-MAX, PDSO8 |
| L7980 | 3.5 A SWITCHING REGULATOR, 1000 kHz SWITCHING FREQ-MAX, PDSO8 |
| L7980TR | 3.5 A SWITCHING REGULATOR, 1000 kHz SWITCHING FREQ-MAX, PDSO8 |
| L7981ATR | SWITCHING REGULATOR, DSO8 |
| L7981TR | SWITCHING REGULATOR, DSO8 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| L7250E1.2 | 功能描述:电源开关 IC - 配电 DSD POWER RoHS:否 制造商:Exar 输出端数量:1 开启电阻（最大值）:85 mOhms 开启时间（最大值）:400 us 关闭时间（最大值）:20 us 工作电源电压:3.2 V to 6.5 V 电源电流（最大值）: 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:SOT-23-5 |
| L7252E2.6 | 功能描述:电源开关 IC - 配电 DSD POWER RoHS:否 制造商:Exar 输出端数量:1 开启电阻（最大值）:85 mOhms 开启时间（最大值）:400 us 关闭时间（最大值）:20 us 工作电源电压:3.2 V to 6.5 V 电源电流（最大值）: 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:SOT-23-5 |
| L725MAG | 制造商:Apex Tool Group 功能描述:TAPE, 1 IN. X 25 FT, 700 SERIES, MAGNETIC END HOOK 制造商:Lufkin 功能描述:TAPE MEASURE, MAGNETIC END HOOK 25FT 1IN; Tape Measure Type:Manual; Measuring Range Max:25ft; Blade Width:1"; Case Color:Orange; Tool Body Material:ABS; Blade Finish:Yellow Clad; Blade Length:25ft ;RoHS Compliant: NA |
| L728 | 制造商:BURNDY 功能描述:L-DIE |
| L7290 | 制造商:CIPS 功能描述:CUTTER OBLIQUE SEMI FLUSH 109MM |
发布紧急采购，3分钟左右您将得到回复。