公开(公告)号：US20120126901A1

公开(公告)日：2012-05-24

申请号：US12948896

申请日：2010-11-18

申请人： Chi Tak (Gerry) LEUNG ,  Chik Wai (David) NG ,  Hing Kit KWAN ,  Wai Kit (Victor) SO ,  Po Wah CHANG ,  Wing Cheong MAK ,  Kwok Kuen KWONG

发明人： Chi Tak (Gerry) LEUNG ,  Chik Wai (David) NG ,  Hing Kit KWAN ,  Wai Kit (Victor) SO ,  Po Wah CHANG ,  Wing Cheong MAK ,  Kwok Kuen KWONG

IPC分类号： H03L7/00

CPC分类号： H03L7/08

摘要： A frequency dithering circuit reduces emissions that cause Electro-Magnetic Interference (EMI) by spreading the spectrum of a clock. The clock sequences a counter that drives a digital count value to a digital-to-analog converter (DAC). The DAC outputs a sawtooth wave with a wide voltage swing. A subtractor scales down the voltage swing to produce a reduced-swing sawtooth wave which is used as an upper limit voltage. Comparators trigger a set-reset latch to toggle the clock when current pumps charge and discharge a capacitor beyond voltage limits. Since the upper limit voltage is the reduced sawtooth wave from the subtractor, the amount of time to charge the capacitor varies, dithering the period of the clock. The degree of dithering can be adjusted by programming the feedback resistance in the subtractor. The subtractor reduces the sensitivity of dithering to errors in the DAC, allowing for an inexpensive, less precise DAC.

摘要翻译： 频率抖动电路通过扩展时钟的频谱来减少引起电磁干扰（EMI）的辐射。 该时钟是将数字计数值驱动到数模转换器（DAC）的计数器。 DAC输出宽电压摆幅的锯齿波。 减法器缩小电压摆幅，产生用作上限电压的减小摆动锯齿波。 当电流泵对电容器充电和放电超过电压限制时，比较器触发设置复位锁存器来切换时钟。 由于上限电压是来自减法器的减少的锯齿波，所以对电容器充电的时间量变化，使时钟的周期抖动。 可以通过对减法器中的反馈电阻进行编程来调整抖动度。 减法器可降低抖动对DAC误差的灵敏度，从而实现廉价，精度更低的DAC。

公开(公告)号：US20120126736A1

公开(公告)日：2012-05-24

申请号：US12948890

申请日：2010-11-18

申请人： Lap Chi (David) LEUNG ,  Yat Tung LAI ,  Chun Fai WONG ,  Kam Hung CHAN ,  Kwok Kuen KWONG

发明人： Lap Chi (David) LEUNG ,  Yat Tung LAI ,  Chun Fai WONG ,  Kam Hung CHAN ,  Kwok Kuen KWONG

IPC分类号： H02P6/14 ,  H02M7/5387

CPC分类号： H03K17/063 ,  H02P7/04 ,  H03K17/0822 ,  H03K2217/0036 ,  H03K2217/0063

摘要： A motor driver circuit for driving the gate node of a high-side driver transistor to a boosted voltage from a charge pump draws little or no static current from the charge pump. The gate node is pulled to the boosted voltage by a p-channel pullup-control transistor that is driven by p-channel transistors that are pumped by capacitors that cut off current flow to ground from the charge pump. An n-channel output-shorting transistor shorts the gate node to the output when the high-side driver is turned off. A coupling capacitor initializes the shorting transistor for each output transition. A p-channel output-sensing transistor generates a feedback to a second stage that drives the coupling capacitor. P-channel diode transistors and an n-channel equalizing transistor control the voltage on the coupling capacitor.

摘要翻译： 用于将高侧驱动晶体管的栅极节点驱动到来自电荷泵的升压电压的电动机驱动器电路很少或没有来自电荷泵的静态电流。 栅极节点被p沟道上拉控制晶体管拉到升压电压，该p沟道上拉控制晶体管由p沟道晶体管驱动，该p沟道晶体管由电容器泵浦，该电流从电荷泵截止电流流向地电。 当高侧驱动器关闭时，n沟道输出短路晶体管将栅极节点短路到输出。 耦合电容器为每个输出跃迁初始化短路晶体管。 p沟道输出感测晶体管产生反馈到驱动耦合电容器的第二级。 P沟道二极管晶体管和n沟道均衡晶体管控制耦合电容上的电压。