AS8410 datasheet(15/19 Pages) AMSCO

15 / 19 page

PWM DC Motor Regulator – Data Sheet

AS8410

Rev. 1.0, December 2000

page 15 of 19

1 This input must be current limited by the external circuitry (max. 400

µA).

2 max. pulse duration = 1

µs

3 valid for I

OUT = 5 mA ... 300 mA and Vbat = 12 V , Vpump = 22 V

4 valid for I

OUT = 1 mA ... 5 mA and VDDA = 12 V , Vpump = 22 V

(For a fixed output current the tolerance of the current amplification factor is less than 10%.)

4.1.4

Charge pump

The charge pump generates a supply voltage about 10 V higher than the system supply voltage

Vbat (Vpump = Vbat + 10 V) to drive the gate of the external high side power FET switch.

In the case of the min. supply voltage Vbat = 6 V, the pumped voltage Vpump is about 11 V.

The load current of the external capacitors Cp1 and Cp2 is limited to max. 40 mA to prevent RF

emissions by high current peaks.

Symbol

Parameter

min

typ

max

Unit

Note

VPP

Pumped voltage difference

VPP = (Vpump – Vbat)

9,0

10,0

12,0

ICp1, ICp2 Currents to the external capacitors

Ripple of the pumped voltage Vpump

0,50

0,70

fPWM

Frequency (internal oscillator)

kHz

1 valid for Vbat = (12.. 33) V (for Vbat = 6 V is VPP = 5 V), Vpump = Vbat + VPP

2 valid for I

Vpump = 300 mA ( pulse duration < 1

µs and f

OSC = 18 kHz ), Cp1 = Cp2 = 400 nF

4.1.5

Motor current measurement unit

The motor measurement unit works with an external current measurement resistor in the high

side motor line. The nominal measurement differential voltage (VCMp – VCMn)nom is fixed to

50 mV (corresponding to 100% of the motor current). So the value of this measurement resistor

is given by Rmeas = 50 mV / Imotor_nom .

The over current detection is fixed by a motor current 60 % over the nominal motor current

(Imotor_over = 1.6 * Imotor_nom). The switch off of the motor in case of an over current (or short circuit

of the motor) is realised in less than 2

µs.

Symbol

Parameter

min

typ

max

Unit

Note

VCMp/CMn Common mode voltage at the pins

CMn or CMp

-1.15

Vbat

VCM_diff_nom Nominal differential voltage of the

motor current measurement input

(VCMp – VCMn)nom

VCM_diff_over Threshold voltage of the over current

detection

1,6 * VCM_diff_nom

Relative motor current measurement

error

1 I

motor_nom = VCM_diff_nom / Rmeas

Rmeas is the motor current measurement resistor.

2 Over current detection at I

motor_over = 1,6 * Imotor_nom

3 FI < 2 % of I

motor_nom

, FI = (Imotor – Imotor_meas) / Imotor_nom

valid for static VCMp/CMn or for: Vbat = 12 V , Vpump = 22 V , switching edges of VCMp/CMn

(VCMp/CMn_min = -0.7 V and VCMp/CMn_max = Vbat) with trise/fall > 200 ns

AS8410 Datasheet(PDF) 15 Page - ams AG

AS8410 Datasheet(HTML) 15 Page - ams AG

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

Datasheet Download

Link URL